diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index 131a69c221d..34fc135fd58 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -1377,6 +1377,8 @@ en:
     email_prefix: "The [label] used in the subject of emails. It will default to 'title' if not set."
     email_site_title: "The title of the site used as the sender of emails from the site. Default to 'title' if not set. If your 'title' contains characters that are not allowed in email sender strings, use this setting."
 
+    find_related_post_with_key: "Only use the reply key to find the replied-to post. (Recommended if using Amazon SES)"
+
     minimum_topics_similar: "How many topics need to exist before similar topics are presented when composing new topics."
 
     relative_date_duration: "Number of days after posting where post dates will be shown as relative (7d) instead of absolute (20 Feb)."
diff --git a/config/site_settings.yml b/config/site_settings.yml
index 441521c33f2..db43496efe7 100644
--- a/config/site_settings.yml
+++ b/config/site_settings.yml
@@ -629,6 +629,8 @@ email:
   alternative_reply_by_email_addresses:
     default: ''
     validator: "AlternativeReplyByEmailAddressesValidator"
+  find_related_post_with_key:
+    default: false
   manual_polling_enabled:
     default: false
   pop3_polling_enabled:
diff --git a/lib/email/receiver.rb b/lib/email/receiver.rb
index ae9caadbd77..56bc320b5aa 100644
--- a/lib/email/receiver.rb
+++ b/lib/email/receiver.rb
@@ -486,6 +486,8 @@ module Email
     end
 
     def find_related_post
+      return if SiteSetting.find_related_post_with_key
+
       message_ids = [@mail.in_reply_to, Email::Receiver.extract_references(@mail.references)]
       message_ids.flatten!
       message_ids.select!(&:present?)