diff --git a/AUTHORS.rst b/AUTHORS.rst
index 4646facb231..1bcd48ae779 100644
--- a/AUTHORS.rst
+++ b/AUTHORS.rst
@@ -69,6 +69,7 @@ Contributors
 * Ian Lee -- quickstart improvements
 * Jacob Mason -- websupport library (GSOC project)
 * James Addison -- linkcheck and HTML search improvements
+* Janne Cederberg -- sphinx.js discovery bug-fix
 * Jeppe Pihl -- literalinclude improvements
 * Jeremy Maitin-Shepard -- C++ domain improvements
 * Joel Wurtz -- cellspanning support in LaTeX
diff --git a/sphinx/builders/html/__init__.py b/sphinx/builders/html/__init__.py
index 16bf66aa9ce..57a718e06d6 100644
--- a/sphinx/builders/html/__init__.py
+++ b/sphinx/builders/html/__init__.py
@@ -190,7 +190,9 @@ def create_build_info(self) -> BuildInfo:
 
     def _get_translations_js(self) -> Path | None:
         for dir_ in self.config.locale_dirs:
-            js_file = Path(dir_, self.config.language, 'LC_MESSAGES', 'sphinx.js')
+            js_file = Path(
+                self.srcdir, dir_, self.config.language, 'LC_MESSAGES', 'sphinx.js'
+            )
             if js_file.is_file():
                 return js_file