diff --git a/src/lib/internationalization/translatable.ts b/src/lib/internationalization/translatable.ts
index d325c69ea..35e319807 100644
--- a/src/lib/internationalization/translatable.ts
+++ b/src/lib/internationalization/translatable.ts
@@ -242,6 +242,7 @@ export const translatable = {
     help_highlightLanguages:
         "Specify the languages which will be loaded to highlight code when rendering",
     help_customCss: "Path to a custom CSS file to for the theme to import",
+    help_customJs: "Path to a custom JS file to import",
     help_markdownItOptions:
         "Specify the options passed to markdown-it, the Markdown parser used by TypeDoc",
     help_markdownItLoader:
diff --git a/src/lib/output/themes/default/layouts/default.tsx b/src/lib/output/themes/default/layouts/default.tsx
index e06c36bf7..a50dab36c 100644
--- a/src/lib/output/themes/default/layouts/default.tsx
+++ b/src/lib/output/themes/default/layouts/default.tsx
@@ -28,6 +28,9 @@ export const defaultLayout = (
             {context.options.getValue("customCss") && (
                 <link rel="stylesheet" href={context.relativeURL("assets/custom.css", true)} />
             )}
+            {context.options.getValue("customJs") && (
+                <script defer src={context.relativeURL("assets/custom.js", true)}></script>
+            )}
             <script defer src={context.relativeURL("assets/main.js", true)}></script>
             <script async src={context.relativeURL("assets/icons.js", true)} id="tsd-icons-script"></script>
             <script async src={context.relativeURL("assets/search.js", true)} id="tsd-search-script"></script>
diff --git a/src/lib/utils/options/declaration.ts b/src/lib/utils/options/declaration.ts
index bd3290e7b..9188a19ba 100644
--- a/src/lib/utils/options/declaration.ts
+++ b/src/lib/utils/options/declaration.ts
@@ -138,6 +138,7 @@ export interface TypeDocOptionMap {
     darkHighlightTheme: ShikiTheme;
     highlightLanguages: string[];
     customCss: string;
+    customJs: string;
     markdownItOptions: ManuallyValidatedOption<Record<string, unknown>>;
     /**
      * Will be called when TypeDoc is setting up the markdown parser to use to render markdown.
diff --git a/src/lib/utils/options/sources/typedoc.ts b/src/lib/utils/options/sources/typedoc.ts
index ad46a33e4..94f9b589c 100644
--- a/src/lib/utils/options/sources/typedoc.ts
+++ b/src/lib/utils/options/sources/typedoc.ts
@@ -329,6 +329,11 @@ export function addTypeDocOptions(options: Pick<Options, "addDeclaration">) {
         help: (i18n) => i18n.help_customCss(),
         type: ParameterType.Path,
     });
+    options.addDeclaration({
+        name: "customJs",
+        help: (i18n) => i18n.help_customJs(),
+        type: ParameterType.Path,
+    });
     options.addDeclaration({
         name: "markdownItOptions",
         help: (i18n) => i18n.help_markdownItOptions(),