diff --git a/build/moz.configure/old.configure b/build/moz.configure/old.configure
index 0561fa8957b5..8ab0b3f13cd3 100644
--- a/build/moz.configure/old.configure
+++ b/build/moz.configure/old.configure
@@ -226,7 +226,6 @@ def old_configure_options(*options):
     '--enable-tasktracer',
     '--enable-thread-sanitizer',
     '--enable-ubsan-int-overflow',
-    '--enable-ui-locale',
     '--enable-universalchardet',
     '--enable-updater',
     '--enable-valgrind',
diff --git a/js/src/old-configure.in b/js/src/old-configure.in
index 62904fbd2ade..6a9016007c01 100644
--- a/js/src/old-configure.in
+++ b/js/src/old-configure.in
@@ -1394,15 +1394,6 @@ dnl =
 dnl ========================================================
 MOZ_ARG_HEADER(Components and Features)
 
-dnl ========================================================
-dnl = Localization
-dnl ========================================================
-MOZ_ARG_ENABLE_STRING(ui-locale,
-[  --enable-ui-locale=ab-CD
-                          Select the user interface locale (default: en-US)],
-    MOZ_UI_LOCALE=$enableval )
-AC_SUBST(MOZ_UI_LOCALE)
-
 dnl ========================================================
 dnl =
 dnl = Module specific options
diff --git a/moz.configure b/moz.configure
index a01a8f406fc7..0b003b26b2e7 100755
--- a/moz.configure
+++ b/moz.configure
@@ -280,6 +280,13 @@ def build_gtest(pgo, build_project, target, automation, enabled, enable_tests):
 
 set_config('LINK_GTEST_DURING_COMPILE', build_gtest)
 
+# Localization
+# ==============================================================
+option('--enable-ui-locale', default='en-US',
+       help='Select the user interface locale (default: en-US)')
+
+set_config('MOZ_UI_LOCALE', depends('--enable-ui-locale')(lambda x: x))
+
 # clang-plugin location
 # ==============================================================
 @depends(library_name_info, check_build_environment, when='--enable-clang-plugin')
diff --git a/old-configure.in b/old-configure.in
index d8d428478bff..ae18382ef6eb 100644
--- a/old-configure.in
+++ b/old-configure.in
@@ -2006,7 +2006,6 @@ MOZ_PREF_EXTENSIONS=1
 MOZ_REFLOW_PERF=
 MOZ_SPELLCHECK=1
 MOZ_TOOLKIT_SEARCH=1
-MOZ_UI_LOCALE=en-US
 MOZ_UNIVERSALCHARDET=1
 MOZ_XUL=1
 MOZ_ZIPWRITER=1
@@ -2267,15 +2266,6 @@ dnl =
 dnl ========================================================
 MOZ_ARG_HEADER(Components and Features)
 
-dnl ========================================================
-dnl = Localization
-dnl ========================================================
-MOZ_ARG_ENABLE_STRING(ui-locale,
-[  --enable-ui-locale=ab-CD
-                          Select the user interface locale (default: en-US)],
-    MOZ_UI_LOCALE=$enableval )
-AC_SUBST(MOZ_UI_LOCALE)
-
 AC_SUBST(MOZ_OFFICIAL_BRANDING)
 if test -n "$MOZ_OFFICIAL_BRANDING"; then
   if test -z "$MOZ_OFFICIAL_BRANDING_DIRECTORY"; then