diff --git a/shell/browser/electron_browser_main_parts.h b/shell/browser/electron_browser_main_parts.h
index 7c8578c957b20..76d5d2d0774fc 100644
--- a/shell/browser/electron_browser_main_parts.h
+++ b/shell/browser/electron_browser_main_parts.h
@@ -130,7 +130,7 @@ class ElectronBrowserMainParts : public content::BrowserMainParts {
   void FreeAppDelegate();
   void RegisterURLHandler();
   void InitializeMainNib();
-  std::string GetCurrentSystemLocale();
+  static std::string GetCurrentSystemLocale();
 #endif
 
 #if BUILDFLAG(IS_MAC)
diff --git a/shell/browser/electron_browser_main_parts_mac.mm b/shell/browser/electron_browser_main_parts_mac.mm
index 2e43c2d81802e..0ae316f20c198 100644
--- a/shell/browser/electron_browser_main_parts_mac.mm
+++ b/shell/browser/electron_browser_main_parts_mac.mm
@@ -76,7 +76,7 @@
   [mainNib release];
 }
 
-std::string ElectronBrowserMainParts::GetCurrentSystemLocale() {
+static std::string ElectronBrowserMainParts::GetCurrentSystemLocale() {
   NSString* systemLocaleIdentifier =
       [[NSLocale currentLocale] localeIdentifier];