diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 0d6a6a39e..cc32da588 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -74,6 +74,9 @@ module I18nHelpers
       def change_locale_and_store_translations(locale, translations, &block)
         current_locale = I18n.locale
         begin
+          # I18n.available_locales needs to be cleared before storing translations:
+          #   https://github.com/svenfuchs/i18n/pull/391
+          I18n.available_locales = nil
           I18n.backend.store_translations locale, translations
           I18n.locale = locale
           yield