diff --git a/packages/docusaurus-module-type-aliases/src/index.d.ts b/packages/docusaurus-module-type-aliases/src/index.d.ts
index ff62e02e2832..1762316fde77 100644
--- a/packages/docusaurus-module-type-aliases/src/index.d.ts
+++ b/packages/docusaurus-module-type-aliases/src/index.d.ts
@@ -280,6 +280,12 @@ declare module '@docusaurus/useDocusaurusContext' {
   export default function useDocusaurusContext(): DocusaurusContext;
 }
 
+declare module '@docusaurus/useThemeConfig' {
+  import type {ThemeConfig} from '@docusaurus/types';
+
+  export default function useThemeConfig(): ThemeConfig;
+}
+
 declare module '@docusaurus/useRouteContext' {
   import type {PluginRouteContext} from '@docusaurus/types';
 
diff --git a/packages/docusaurus-preset-classic/src/options.ts b/packages/docusaurus-preset-classic/src/options.ts
index 6ac62497e7eb..6363bc478f6c 100644
--- a/packages/docusaurus-preset-classic/src/options.ts
+++ b/packages/docusaurus-preset-classic/src/options.ts
@@ -5,6 +5,9 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+// Adds the Algolia fields to the @docusaurus/types UserThemeConfig interface
+/// <reference types="@docusaurus/theme-search-algolia" preserve="true" />
+
 import type {Options as DocsPluginOptions} from '@docusaurus/plugin-content-docs';
 import type {Options as BlogPluginOptions} from '@docusaurus/plugin-content-blog';
 import type {Options as PagesPluginOptions} from '@docusaurus/plugin-content-pages';
@@ -14,9 +17,8 @@ import type {Options as GtagPluginOptions} from '@docusaurus/plugin-google-gtag'
 import type {Options as GTMPluginOptions} from '@docusaurus/plugin-google-tag-manager';
 import type {Options as CssCascadeLayersPluginOptions} from '@docusaurus/plugin-css-cascade-layers';
 import type {Options as ThemeOptions} from '@docusaurus/theme-classic';
-import type {ThemeConfig as BaseThemeConfig} from '@docusaurus/types';
-import type {UserThemeConfig as ClassicThemeConfig} from '@docusaurus/theme-common';
-import type {UserThemeConfig as AlgoliaThemeConfig} from '@docusaurus/theme-search-algolia';
+// Importing from theme-common also adds the classic theme fields
+import type {UserThemeConfig} from '@docusaurus/theme-common';
 
 export type Options = {
   /**
@@ -49,6 +51,5 @@ export type Options = {
   cssCascadeLayers?: false | CssCascadeLayersPluginOptions;
 };
 
-export type ThemeConfig = BaseThemeConfig &
-  ClassicThemeConfig &
-  AlgoliaThemeConfig;
+// Theme config fields of all the themes of this preset, including Algolia's
+export type ThemeConfig = UserThemeConfig;
diff --git a/packages/docusaurus-theme-classic/src/options.ts b/packages/docusaurus-theme-classic/src/options.ts
index 52501b718ab9..d310544ef1ab 100644
--- a/packages/docusaurus-theme-classic/src/options.ts
+++ b/packages/docusaurus-theme-classic/src/options.ts
@@ -13,6 +13,7 @@ import type {
 } from '@theme/NavbarItem/DocsVersionDropdownNavbarItem';
 import type {Options, PluginOptions} from '@docusaurus/theme-classic';
 import type {ThemeConfig} from '@docusaurus/theme-common';
+import type {ClassicThemeConfig} from '@docusaurus/theme-common/internal';
 import type {
   ThemeConfigValidationContext,
   OptionValidationContext,
@@ -58,7 +59,7 @@ const DEFAULT_COLOR_MODE_CONFIG: ThemeConfig['colorMode'] = {
   respectPrefersColorScheme: false,
 };
 
-export const DEFAULT_CONFIG: ThemeConfig = {
+export const DEFAULT_CONFIG: ClassicThemeConfig = {
   colorMode: DEFAULT_COLOR_MODE_CONFIG,
   docs: DEFAULT_DOCS_CONFIG,
   blog: DEFAULT_BLOG_CONFIG,
diff --git a/packages/docusaurus-theme-common/src/internal.ts b/packages/docusaurus-theme-common/src/internal.ts
index fa8979347891..ece229aeb8cb 100644
--- a/packages/docusaurus-theme-common/src/internal.ts
+++ b/packages/docusaurus-theme-common/src/internal.ts
@@ -31,6 +31,8 @@ export {
 } from './utils/tabsUtils';
 export type {TabValue, TabsProps, TabItemProps} from './utils/tabsUtils';
 
+export type {ClassicThemeConfig} from './utils/useThemeConfig';
+
 export {useNavbarMobileSidebar} from './contexts/navbarMobileSidebar';
 export {useNavbarSecondaryMenu} from './contexts/navbarSecondaryMenu/display';
 
diff --git a/packages/docusaurus-theme-common/src/utils/useThemeConfig.ts b/packages/docusaurus-theme-common/src/utils/useThemeConfig.ts
index d15df936d1fa..d3eed612ef0e 100644
--- a/packages/docusaurus-theme-common/src/utils/useThemeConfig.ts
+++ b/packages/docusaurus-theme-common/src/utils/useThemeConfig.ts
@@ -5,9 +5,10 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import useDocusaurusContext from '@docusaurus/useDocusaurusContext';
+import useCoreThemeConfig from '@docusaurus/useThemeConfig';
 import type {PrismTheme} from 'prism-react-renderer';
 import type {DeepPartial} from 'utility-types';
+import type {ThemeConfig, UserThemeConfig} from '@docusaurus/types';
 import type {MagicCommentConfig} from './codeBlockUtils';
 import type {ColorMode} from '../contexts/colorMode';
 
@@ -104,9 +105,8 @@ type TableOfContents = {
   maxHeadingLevel: number;
 };
 
-// TODO Docusaurus v4: use interface + declaration merging to enhance
-// Theme config after validation/normalization
-export type ThemeConfig = {
+// Theme config fields of the classic theme, after validation/normalization
+export type ClassicThemeConfig = {
   docs: {
     versionPersistence: DocsVersionPersistence;
     sidebar: {
@@ -136,12 +136,17 @@ export type ThemeConfig = {
   tableOfContents: TableOfContents;
 };
 
-// User-provided theme config, unnormalized
-export type UserThemeConfig = DeepPartial<ThemeConfig>;
+// Adds the classic theme fields to the @docusaurus/types interfaces
+declare module '@docusaurus/types' {
+  interface ThemeConfig extends ClassicThemeConfig {}
+  interface UserThemeConfig extends DeepPartial<ClassicThemeConfig> {}
+}
+
+export type {ThemeConfig, UserThemeConfig};
 
 /**
- * A convenient/more semantic way to get theme config from context.
+ * Same as the `@docusaurus/useThemeConfig` hook of Docusaurus core.
  */
 export function useThemeConfig(): ThemeConfig {
-  return useDocusaurusContext().siteConfig.themeConfig as ThemeConfig;
+  return useCoreThemeConfig();
 }
diff --git a/packages/docusaurus-theme-live-codeblock/src/__tests__/validateThemeConfig.test.ts b/packages/docusaurus-theme-live-codeblock/src/__tests__/validateThemeConfig.test.ts
index 8ad793e64055..91c3b062070c 100644
--- a/packages/docusaurus-theme-live-codeblock/src/__tests__/validateThemeConfig.test.ts
+++ b/packages/docusaurus-theme-live-codeblock/src/__tests__/validateThemeConfig.test.ts
@@ -8,12 +8,10 @@
 import {describe, expect, it} from 'vitest';
 import {validateThemeConfig, DEFAULT_CONFIG} from '../validateThemeConfig';
 import type {Joi} from '@docusaurus/utils-validation';
+import type {ThemeConfig} from '@docusaurus/theme-live-codeblock';
 
 function testValidateThemeConfig(themeConfig: {[key: string]: unknown}) {
-  function validate(
-    schema: Joi.ObjectSchema<{[key: string]: unknown}>,
-    cfg: {[key: string]: unknown},
-  ) {
+  function validate(schema: Joi.ObjectSchema<ThemeConfig>, cfg: ThemeConfig) {
     const {value, error} = schema.validate(cfg, {
       convert: false,
     });
@@ -23,7 +21,11 @@ function testValidateThemeConfig(themeConfig: {[key: string]: unknown}) {
     return value;
   }
 
-  return validateThemeConfig({validate, themeConfig});
+  // Some tests pass invalid theme configs on purpose
+  return validateThemeConfig({
+    validate,
+    themeConfig: themeConfig as ThemeConfig,
+  });
 }
 
 describe('validateThemeConfig', () => {
diff --git a/packages/docusaurus-theme-live-codeblock/src/theme-live-codeblock.d.ts b/packages/docusaurus-theme-live-codeblock/src/theme-live-codeblock.d.ts
index 550623f1fa31..0fe0b13b87b3 100644
--- a/packages/docusaurus-theme-live-codeblock/src/theme-live-codeblock.d.ts
+++ b/packages/docusaurus-theme-live-codeblock/src/theme-live-codeblock.d.ts
@@ -11,11 +11,26 @@
 declare module '@docusaurus/theme-live-codeblock' {
   import type {PlaygroundPosition} from '@theme/Playground';
 
+  export type ThemeConfigLiveCodeBlock = {
+    playgroundPosition: PlaygroundPosition;
+  };
+
   export type ThemeConfig = {
-    liveCodeBlock: {
-      playgroundPosition: PlaygroundPosition;
-    };
+    liveCodeBlock: ThemeConfigLiveCodeBlock;
   };
+
+  // Adds the theme config fields to the @docusaurus/types interfaces
+  // Their names intentionally shadow the ThemeConfig types of this module
+  /* eslint-disable @typescript-eslint/no-shadow */
+  module '@docusaurus/types' {
+    interface ThemeConfig {
+      liveCodeBlock: ThemeConfigLiveCodeBlock;
+    }
+    interface UserThemeConfig {
+      liveCodeBlock?: Partial<ThemeConfigLiveCodeBlock>;
+    }
+  }
+  /* eslint-enable @typescript-eslint/no-shadow */
 }
 
 declare module '@theme/LiveCodeBlock' {
diff --git a/packages/docusaurus-theme-live-codeblock/src/theme/Playground/Layout/index.tsx b/packages/docusaurus-theme-live-codeblock/src/theme/Playground/Layout/index.tsx
index 157b7993e887..2d563d7a278f 100644
--- a/packages/docusaurus-theme-live-codeblock/src/theme/Playground/Layout/index.tsx
+++ b/packages/docusaurus-theme-live-codeblock/src/theme/Playground/Layout/index.tsx
@@ -6,20 +6,13 @@
  */
 
 import type {ReactNode} from 'react';
-import {useThemeConfig} from '@docusaurus/theme-common';
+import useThemeConfig from '@docusaurus/useThemeConfig';
 import PlaygroundPreview from '@theme/Playground/Preview';
 import PlaygroundEditor from '@theme/Playground/Editor';
 import type {Props} from '@theme/Playground/Layout';
 
-import type {ThemeConfig} from '@docusaurus/theme-live-codeblock';
-
-function useLiveCodeBlockThemeConfig() {
-  const themeConfig = useThemeConfig() as unknown as ThemeConfig;
-  return themeConfig.liveCodeBlock;
-}
-
 export default function PlaygroundLayout(props: Props): ReactNode {
-  const themeConfig = useLiveCodeBlockThemeConfig();
+  const themeConfig = useThemeConfig().liveCodeBlock;
   const position = props.position ?? themeConfig.playgroundPosition;
   return (
     <>
diff --git a/packages/docusaurus-theme-live-codeblock/src/validateThemeConfig.ts b/packages/docusaurus-theme-live-codeblock/src/validateThemeConfig.ts
index d642214987de..7a3421df8eb9 100644
--- a/packages/docusaurus-theme-live-codeblock/src/validateThemeConfig.ts
+++ b/packages/docusaurus-theme-live-codeblock/src/validateThemeConfig.ts
@@ -6,10 +6,8 @@
  */
 
 import {Joi} from '@docusaurus/utils-validation';
-import type {
-  ThemeConfig,
-  ThemeConfigValidationContext,
-} from '@docusaurus/types';
+import type {ThemeConfig} from '@docusaurus/theme-live-codeblock';
+import type {ThemeConfigValidationContext} from '@docusaurus/types';
 
 export const DEFAULT_CONFIG = {
   playgroundPosition: 'bottom',
diff --git a/packages/docusaurus-theme-mermaid/src/client/index.ts b/packages/docusaurus-theme-mermaid/src/client/index.ts
index c850cce7cad4..50c7cec8edb3 100644
--- a/packages/docusaurus-theme-mermaid/src/client/index.ts
+++ b/packages/docusaurus-theme-mermaid/src/client/index.ts
@@ -6,17 +6,18 @@
  */
 
 import {useState, useEffect, useMemo, useId, useRef} from 'react';
-import {useColorMode, useThemeConfig} from '@docusaurus/theme-common';
+import useThemeConfig from '@docusaurus/useThemeConfig';
+import {useColorMode} from '@docusaurus/theme-common';
 import {loadMermaid} from './loadMermaid';
 
 import type {RenderResult, MermaidConfig} from 'mermaid';
-import type {ThemeConfig} from '@docusaurus/theme-mermaid';
+import type {ThemeConfigMermaid} from '@docusaurus/theme-mermaid';
 
 // Stable className to allow users to easily target with CSS
 export const MermaidContainerClassName = 'docusaurus-mermaid-container';
 
-export function useMermaidThemeConfig(): ThemeConfig['mermaid'] {
-  return (useThemeConfig() as unknown as ThemeConfig).mermaid;
+export function useMermaidThemeConfig(): ThemeConfigMermaid {
+  return useThemeConfig().mermaid;
 }
 
 export function useMermaidConfig(): MermaidConfig {
diff --git a/packages/docusaurus-theme-mermaid/src/theme-mermaid.d.ts b/packages/docusaurus-theme-mermaid/src/theme-mermaid.d.ts
index 33142adbd423..395e34460a48 100644
--- a/packages/docusaurus-theme-mermaid/src/theme-mermaid.d.ts
+++ b/packages/docusaurus-theme-mermaid/src/theme-mermaid.d.ts
@@ -12,17 +12,32 @@ declare module '@docusaurus/theme-mermaid' {
   import type {MermaidConfig} from 'mermaid';
   import type {Plugin} from '@docusaurus/types';
 
-  export type ThemeConfig = {
-    mermaid: {
-      theme: {
-        light: NonNullable<MermaidConfig['theme']>;
-        dark: NonNullable<MermaidConfig['theme']>;
-      };
-      options: MermaidConfig;
+  export type ThemeConfigMermaid = {
+    theme: {
+      light: NonNullable<MermaidConfig['theme']>;
+      dark: NonNullable<MermaidConfig['theme']>;
     };
+    options: MermaidConfig;
+  };
+
+  export type ThemeConfig = {
+    mermaid: ThemeConfigMermaid;
   };
   export type UserThemeConfig = DeepPartial<ThemeConfig>;
 
+  // Adds the theme config fields to the @docusaurus/types interfaces
+  // Their names intentionally shadow the ThemeConfig types of this module
+  /* eslint-disable @typescript-eslint/no-shadow */
+  module '@docusaurus/types' {
+    interface ThemeConfig {
+      mermaid: ThemeConfigMermaid;
+    }
+    interface UserThemeConfig {
+      mermaid?: DeepPartial<ThemeConfigMermaid>;
+    }
+  }
+  /* eslint-enable @typescript-eslint/no-shadow */
+
   export default function themeMermaid(): Plugin<undefined>;
 }
 
diff --git a/packages/docusaurus-theme-search-algolia/src/theme-search-algolia.d.ts b/packages/docusaurus-theme-search-algolia/src/theme-search-algolia.d.ts
index c9360342fd93..d4b5778add2e 100644
--- a/packages/docusaurus-theme-search-algolia/src/theme-search-algolia.d.ts
+++ b/packages/docusaurus-theme-search-algolia/src/theme-search-algolia.d.ts
@@ -59,25 +59,40 @@ declare module '@docusaurus/theme-search-algolia' {
     };
   };
 
+  export type UserThemeConfigAlgolia = Overwrite<
+    DeepPartial<ThemeConfigAlgolia>,
+    {
+      // Required fields:
+      appId: ThemeConfigAlgolia['appId'];
+      apiKey: ThemeConfigAlgolia['apiKey'];
+      indexName: ThemeConfigAlgolia['indexName'];
+      // askAi also accepts a shorter string form
+      askAi?: string | Optional<AskAiConfig, 'indexName' | 'appId' | 'apiKey'>;
+    }
+  >;
+
   export type ThemeConfig = {
     algolia: ThemeConfigAlgolia;
   };
 
   export type UserThemeConfig = {
-    algolia?: Overwrite<
-      DeepPartial<ThemeConfigAlgolia>,
-      {
-        // Required fields:
-        appId: ThemeConfigAlgolia['appId'];
-        apiKey: ThemeConfigAlgolia['apiKey'];
-        indexName: ThemeConfigAlgolia['indexName'];
-        // askAi also accepts a shorter string form
-        askAi?:
-          | string
-          | Optional<AskAiConfig, 'indexName' | 'appId' | 'apiKey'>;
-      }
-    >;
+    algolia?: UserThemeConfigAlgolia;
   };
+
+  // Adds the theme config fields to the @docusaurus/types interfaces
+  // Their names intentionally shadow the ThemeConfig types of this module
+  /* eslint-disable @typescript-eslint/no-shadow */
+  module '@docusaurus/types' {
+    interface ThemeConfig {
+      // Optional: the classic preset only enables this theme when the
+      // "algolia" field is provided
+      algolia?: ThemeConfigAlgolia;
+    }
+    interface UserThemeConfig {
+      algolia?: UserThemeConfigAlgolia;
+    }
+  }
+  /* eslint-enable @typescript-eslint/no-shadow */
 }
 
 declare module '@theme/SearchPage' {
diff --git a/packages/docusaurus-theme-search-algolia/src/theme/SearchBar/index.tsx b/packages/docusaurus-theme-search-algolia/src/theme/SearchBar/index.tsx
index 6b46c11930ad..aa0cd473396e 100644
--- a/packages/docusaurus-theme-search-algolia/src/theme/SearchBar/index.tsx
+++ b/packages/docusaurus-theme-search-algolia/src/theme/SearchBar/index.tsx
@@ -15,6 +15,7 @@ import {useHistory} from '@docusaurus/router';
 import {isRegexpStringMatch} from '@docusaurus/theme-common';
 import {
   useAlgoliaContextualFacetFilters,
+  useAlgoliaThemeConfig,
   useSearchResultUrlProcessor,
   useAlgoliaAskAi,
   mergeFacetFilters,
@@ -310,14 +311,14 @@ function DocSearch({externalUrlRegex, ...props}: DocSearchV4Props) {
 }
 
 export default function SearchBar(props: Partial<DocSearchV4Props>): ReactNode {
-  const {siteConfig} = useDocusaurusContext();
+  const {algolia} = useAlgoliaThemeConfig();
 
-  const docSearchProps: DocSearchV4Props = {
-    ...(siteConfig.themeConfig.algolia as DocSearchV4Props),
+  const docSearchProps = {
+    ...algolia,
     // Let props override theme config
     // See https://github.com/facebook/docusaurus/pull/11581
     ...props,
-  };
+  } as DocSearchV4Props;
 
   return <DocSearch {...docSearchProps} />;
 }
diff --git a/packages/docusaurus-types/src/config.d.ts b/packages/docusaurus-types/src/config.d.ts
index 96dff8c2ac0a..4c63b9d6eb62 100644
--- a/packages/docusaurus-types/src/config.d.ts
+++ b/packages/docusaurus-types/src/config.d.ts
@@ -15,9 +15,32 @@ import type {MarkdownConfig} from './markdown';
 
 export type RouterType = 'browser' | 'hash';
 
-export type ThemeConfig = {
+/**
+ * Theme config, after validation and normalization by themes and plugins.
+ *
+ * Themes and plugins can declare their own fields with declaration merging:
+ *
+ * ```ts
+ * declare module '@docusaurus/types' {
+ *   interface ThemeConfig {
+ *     myTheme: {position: 'top' | 'bottom'};
+ *   }
+ * }
+ * ```
+ */
+export interface ThemeConfig {
   [key: string]: unknown;
-};
+}
+
+/**
+ * Theme config, as written by users in their site config, before validation.
+ *
+ * Themes and plugins can declare their own fields with declaration merging,
+ * like for {@link ThemeConfig}.
+ */
+export interface UserThemeConfig {
+  [key: string]: unknown;
+}
 
 export type StorageConfig = {
   type: SiteStorage['type'];
@@ -403,5 +426,6 @@ export type Config = Overwrite<
      */
     webpack?: boolean | WebpackConfig;
     future?: DeepPartial<FutureConfig>;
+    themeConfig?: UserThemeConfig;
   }
 >;
diff --git a/packages/docusaurus-types/src/index.d.ts b/packages/docusaurus-types/src/index.d.ts
index c523c79e4fb8..07abf4e4cd0b 100644
--- a/packages/docusaurus-types/src/index.d.ts
+++ b/packages/docusaurus-types/src/index.d.ts
@@ -8,6 +8,7 @@
 export {
   RouterType,
   ThemeConfig,
+  UserThemeConfig,
   DocusaurusConfig,
   FutureConfig,
   WebpackConfig,
diff --git a/packages/docusaurus/src/client/exports/useThemeConfig.ts b/packages/docusaurus/src/client/exports/useThemeConfig.ts
new file mode 100644
index 000000000000..e99e4aed8070
--- /dev/null
+++ b/packages/docusaurus/src/client/exports/useThemeConfig.ts
@@ -0,0 +1,13 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import useDocusaurusContext from './useDocusaurusContext';
+import type {ThemeConfig} from '@docusaurus/types';
+
+export default function useThemeConfig(): ThemeConfig {
+  return useDocusaurusContext().siteConfig.themeConfig;
+}
diff --git a/packages/docusaurus/src/server/configValidation.ts b/packages/docusaurus/src/server/configValidation.ts
index cbd96ef3595f..8d656833477d 100644
--- a/packages/docusaurus/src/server/configValidation.ts
+++ b/packages/docusaurus/src/server/configValidation.ts
@@ -27,6 +27,7 @@ import type {
   MarkdownConfig,
   MarkdownHooks,
   StorageConfig,
+  ThemeConfig,
   VcsConfig,
   VcsPreset,
   WebpackConfig,
@@ -142,7 +143,8 @@ export const DEFAULT_CONFIG: Pick<
   scripts: [],
   clientModules: [],
   customFields: {},
-  themeConfig: {},
+  // Themes add their own fields when validating the theme config
+  themeConfig: {} as ThemeConfig,
   titleDelimiter: '|',
   noIndex: false,
   tagline: '',
diff --git a/packages/docusaurus/src/webpack/__tests__/__snapshots__/base.test.ts.snap b/packages/docusaurus/src/webpack/__tests__/__snapshots__/base.test.ts.snap
index 997ed1b3f24f..ea927f171235 100644
--- a/packages/docusaurus/src/webpack/__tests__/__snapshots__/base.test.ts.snap
+++ b/packages/docusaurus/src/webpack/__tests__/__snapshots__/base.test.ts.snap
@@ -22,6 +22,7 @@ exports[`base webpack config > creates webpack aliases 1`] = `
   "@docusaurus/useIsBrowser": "../../../../client/exports/useIsBrowser.ts",
   "@docusaurus/useIsomorphicLayoutEffect": "../../../../client/exports/useIsomorphicLayoutEffect.tsx",
   "@docusaurus/useRouteContext": "../../../../client/exports/useRouteContext.tsx",
+  "@docusaurus/useThemeConfig": "../../../../client/exports/useThemeConfig.ts",
   "@generated": "../../../../../../..",
   "@mdx-js/react": "../../../../../../../node_modules/@mdx-js/react",
   "@site": "",
diff --git a/packages/docusaurus/src/webpack/aliases/__tests__/__snapshots__/index.test.ts.snap b/packages/docusaurus/src/webpack/aliases/__tests__/__snapshots__/index.test.ts.snap
index 50f0f435fe47..137839bad8f2 100644
--- a/packages/docusaurus/src/webpack/aliases/__tests__/__snapshots__/index.test.ts.snap
+++ b/packages/docusaurus/src/webpack/aliases/__tests__/__snapshots__/index.test.ts.snap
@@ -22,6 +22,7 @@ exports[`getDocusaurusAliases > returns appropriate webpack aliases 1`] = `
   "@docusaurus/useIsBrowser": "<PROJECT_ROOT>/packages/docusaurus/src/client/exports/useIsBrowser.ts",
   "@docusaurus/useIsomorphicLayoutEffect": "<PROJECT_ROOT>/packages/docusaurus/src/client/exports/useIsomorphicLayoutEffect.tsx",
   "@docusaurus/useRouteContext": "<PROJECT_ROOT>/packages/docusaurus/src/client/exports/useRouteContext.tsx",
+  "@docusaurus/useThemeConfig": "<PROJECT_ROOT>/packages/docusaurus/src/client/exports/useThemeConfig.ts",
 }
 `;
 
diff --git a/website/docs/api/plugin-methods/static-methods.mdx b/website/docs/api/plugin-methods/static-methods.mdx
index 6cd5e5124e58..e29f1cab5309 100644
--- a/website/docs/api/plugin-methods/static-methods.mdx
+++ b/website/docs/api/plugin-methods/static-methods.mdx
@@ -81,3 +81,20 @@ export function validateThemeConfig({themeConfig, validate}) {
 }
 // highlight-end
 ```
+
+### TypeScript types {/* #validateThemeConfig-types */}
+
+The `@docusaurus/types` package declares the theme config types with 2 interfaces: `ThemeConfig` after validation and normalization, and `UserThemeConfig` as written in `docusaurus.config.js`. Your theme can add its own fields to them with TypeScript [declaration merging](https://www.typescriptlang.org/docs/handbook/declaration-merging.html#module-augmentation):
+
+```ts title="my-theme/src/index.ts"
+declare module '@docusaurus/types' {
+  interface ThemeConfig {
+    myTheme: {position: 'top' | 'bottom'};
+  }
+  interface UserThemeConfig {
+    myTheme?: {position?: 'top' | 'bottom'};
+  }
+}
+```
+
+Once your theme types are loaded, [`useThemeConfig()`](../../docusaurus-core.mdx#useThemeConfig) returns a typed `myTheme` field, and site authors get autocompletion for `myTheme` in their `themeConfig`.
diff --git a/website/docs/docusaurus-core.mdx b/website/docs/docusaurus-core.mdx
index f5f15b989e89..bcdff16ce328 100644
--- a/website/docs/docusaurus-core.mdx
+++ b/website/docs/docusaurus-core.mdx
@@ -407,6 +407,25 @@ The `siteConfig` object only contains **serializable values** (values that are p
 
 :::
 
+### `useThemeConfig` {/* #useThemeConfig */}
+
+React hook to access the [`themeConfig`](api/docusaurus.config.js.mdx#themeConfig) object of the site, after themes and plugins have [validated and normalized it](api/plugin-methods/static-methods.mdx#validateThemeConfig).
+
+Its TypeScript type includes the fields declared by the themes and plugins you installed.
+
+Usage example:
+
+```jsx
+import React from 'react';
+import useThemeConfig from '@docusaurus/useThemeConfig';
+
+const MyComponent = () => {
+  // highlight-next-line
+  const {navbar} = useThemeConfig();
+  return <div>{navbar.title}</div>;
+};
+```
+
 ### `useIsBrowser` {/* #useIsBrowser */}
 
 Returns `true` after initial hydration completes in the browser.
diff --git a/website/docusaurus.config.ts b/website/docusaurus.config.ts
index 2c1b5f4c769e..81466d301a48 100644
--- a/website/docusaurus.config.ts
+++ b/website/docusaurus.config.ts
@@ -4,6 +4,10 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
+
+// Adds the liveCodeBlock fields to the Preset.ThemeConfig type
+/// <reference types="@docusaurus/theme-live-codeblock" />
+
 import path from 'node:path';
 
 import npm2yarn from '@docusaurus/remark-plugin-npm2yarn';
@@ -34,9 +38,6 @@ import type {Options as BlogOptions} from '@docusaurus/plugin-content-blog';
 import type {Options as PageOptions} from '@docusaurus/plugin-content-pages';
 import type {Options as IdealImageOptions} from '@docusaurus/plugin-ideal-image';
 import type {Options as ClientRedirectsOptions} from '@docusaurus/plugin-client-redirects';
-import type {ThemeConfig as LiveCodeBlockThemeConfig} from '@docusaurus/theme-live-codeblock';
-
-type ThemeConfig = Preset.ThemeConfig & LiveCodeBlockThemeConfig;
 
 const ArchivedVersionsDropdownItems = Object.entries(VersionsArchived).splice(
   0,
@@ -887,6 +888,6 @@ export default async function createConfigAsync() {
         },
         copyright: `Copyright © ${new Date().getFullYear()} Meta Platforms, Inc. Built with Docusaurus.`,
       },
-    } satisfies ThemeConfig,
+    } satisfies Preset.ThemeConfig,
   } satisfies Config;
 }