diff --git a/app/mailers/user_notifications.rb b/app/mailers/user_notifications.rb
index 9aca0902eba..81ea701312f 100644
--- a/app/mailers/user_notifications.rb
+++ b/app/mailers/user_notifications.rb
@@ -11,37 +11,43 @@ class UserNotifications < ActionMailer::Base
   def signup(user, opts={})
     build_email(user.email,
                 template: "user_notifications.signup",
+                locale: user_locale(user),
                 email_token: opts[:email_token])
   end
 
   def signup_after_approval(user, opts={})
     build_email(user.email,
                 template: 'user_notifications.signup_after_approval',
+                locale: user_locale(user),
                 email_token: opts[:email_token],
-                new_user_tips: I18n.t('system_messages.usage_tips.text_body_template', base_url: Discourse.base_url))
+                new_user_tips: I18n.t('system_messages.usage_tips.text_body_template', base_url: Discourse.base_url, locale: locale))
   end
 
   def authorize_email(user, opts={})
     build_email(user.email,
                 template: "user_notifications.authorize_email",
+                locale: user_locale(user),
                 email_token: opts[:email_token])
   end
 
   def forgot_password(user, opts={})
     build_email(user.email,
                 template: user.has_password? ? "user_notifications.forgot_password" : "user_notifications.set_password",
+                locale: user_locale(user),
                 email_token: opts[:email_token])
   end
 
   def admin_login(user, opts={})
     build_email(user.email,
                 template: "user_notifications.admin_login",
+                locale: user_locale(user),
                 email_token: opts[:email_token])
   end
 
   def account_created(user, opts={})
     build_email(user.email,
                 template: "user_notifications.account_created",
+                locale: user_locale(user),
                 email_token: opts[:email_token])
   end
 
@@ -181,6 +187,10 @@ class UserNotifications < ActionMailer::Base
 
   protected
 
+  def user_locale(user)
+    user.respond_to?(:locale) ? user.locale : nil
+  end
+
   def email_post_markdown(post)
     result = "[email-indent]\n"
     result << "#{post.raw}\n\n"
@@ -264,6 +274,7 @@ class UserNotifications < ActionMailer::Base
     from_alias = opts[:from_alias]
     notification_type = opts[:notification_type]
     user = opts[:user]
+    locale = user_locale(user)
 
     # category name
     category = Topic.find_by(id: post.topic_id).category
@@ -338,6 +349,7 @@ class UserNotifications < ActionMailer::Base
       site_description: SiteSetting.site_description,
       site_title: SiteSetting.title,
       style: :notification,
+      locale: locale
     }
 
     # If we have a display name, change the from address
diff --git a/lib/email/message_builder.rb b/lib/email/message_builder.rb
index efa0eeab407..991620e3ad8 100644
--- a/lib/email/message_builder.rb
+++ b/lib/email/message_builder.rb
@@ -28,7 +28,7 @@ module Email
       }.merge!(@opts)
 
       if @template_args[:url].present?
-        @template_args[:header_instructions] = I18n.t('user_notifications.header_instructions')
+        @template_args[:header_instructions] = I18n.t('user_notifications.header_instructions', locale: @opts[:locale])
 
         if @opts[:include_respond_instructions] == false
           @template_args[:respond_instructions] = ''
@@ -67,7 +67,7 @@ module Email
         html_override.gsub!("%{unsubscribe_link}", unsubscribe_link)
 
         if SiteSetting.unsubscribe_via_email_footer && @opts[:add_unsubscribe_via_email_link]
-          unsubscribe_via_email_link = PrettyText.cook(I18n.t('unsubscribe_via_email_link', hostname: Discourse.current_hostname), sanitize: false).html_safe
+          unsubscribe_via_email_link = PrettyText.cook(I18n.t('unsubscribe_via_email_link', hostname: Discourse.current_hostname, locale: @opts[:locale]), sanitize: false).html_safe
           html_override.gsub!("%{unsubscribe_via_email_link}", unsubscribe_via_email_link)
         else
           html_override.gsub!("%{unsubscribe_via_email_link}", "")
@@ -114,7 +114,7 @@ module Email
         body << "\n"
         body << I18n.t('unsubscribe_link', template_args)
         if SiteSetting.unsubscribe_via_email_footer && @opts[:add_unsubscribe_via_email_link]
-          body << I18n.t('unsubscribe_via_email_link', hostname: Discourse.current_hostname)
+          body << I18n.t('unsubscribe_via_email_link', hostname: Discourse.current_hostname, locale: @opts[:locale])
         end
       end
 
diff --git a/spec/mailers/user_notifications_spec.rb b/spec/mailers/user_notifications_spec.rb
index 4123b40da14..29466c08c02 100644
--- a/spec/mailers/user_notifications_spec.rb
+++ b/spec/mailers/user_notifications_spec.rb
@@ -268,6 +268,15 @@ describe UserNotifications do
     end
   end
 
+  # The parts of emails that are derived from templates are translated
+  shared_examples "sets user locale" do
+    context "set locale for translating templates" do
+      it "sets the locale" do
+        expects_build_with(has_key(:locale))
+      end
+    end
+  end
+
   shared_examples "notification email building" do
     let(:post) { Fabricate(:post, user: user) }
     let(:mail_type) { "user_#{notification_type}"}
@@ -341,6 +350,7 @@ describe UserNotifications do
     include_examples "notification email building" do
       let(:notification_type) { :mentioned }
       include_examples "supports reply by email"
+      include_examples "sets user locale"
     end
   end
 
@@ -348,6 +358,7 @@ describe UserNotifications do
     include_examples "notification email building" do
       let(:notification_type) { :replied }
       include_examples "supports reply by email"
+      include_examples "sets user locale"
     end
   end
 
@@ -355,6 +366,7 @@ describe UserNotifications do
     include_examples "notification email building" do
       let(:notification_type) { :quoted }
       include_examples "supports reply by email"
+      include_examples "sets user locale"
     end
   end
 
@@ -362,6 +374,7 @@ describe UserNotifications do
     include_examples "notification email building" do
       let(:notification_type) { :posted }
       include_examples "supports reply by email"
+      include_examples "sets user locale"
     end
   end
 
@@ -369,6 +382,7 @@ describe UserNotifications do
     include_examples "notification email building" do
       let(:notification_type) { :invited_to_private_message }
       include_examples "no reply by email"
+      include_examples "sets user locale"
     end
   end
 
@@ -376,7 +390,44 @@ describe UserNotifications do
     include_examples "notification email building" do
       let(:notification_type) { :invited_to_topic }
       include_examples "no reply by email"
+      include_examples "sets user locale"
     end
   end
 
+  # notification emails derived from templates are translated into the user's locale
+  shared_examples "notification derived from template" do
+    let(:user) { Fabricate(:user, locale: locale) }
+    let(:mail_type) { mail_type }
+    let(:notification) { Fabricate(:notification, user: user) }
+  end
+
+  describe "notifications from template" do
+
+    context "user locale has been set" do
+
+      %w(signup signup_after_approval authorize_email forgot_password admin_login account_created).each do |mail_type|
+        include_examples "notification derived from template" do
+          SiteSetting.default_locale = "en"
+          let(:locale) { "fr" }
+          let(:mail_type) { mail_type }
+          it "sets the locale" do
+            expects_build_with(has_entry(:locale, "fr"))
+          end
+        end
+      end
+    end
+
+    context "user locale has not been set" do
+      %w(signup signup_after_approval authorize_email forgot_password admin_login account_created).each do |mail_type|
+        include_examples "notification derived from template" do
+          SiteSetting.default_locale = "en"
+          let(:locale) { nil }
+          let(:mail_type) { mail_type }
+          it "sets the locale" do
+            expects_build_with(has_entry(:locale, nil))
+          end
+        end
+      end
+    end
+  end
 end