diff --git a/chatcommands.py b/chatcommands.py
index 91706e88e4..a769f444a4 100644
--- a/chatcommands.py
+++ b/chatcommands.py
@@ -700,7 +700,11 @@ def approve(msg, pr_id):
         raise CmdException(str(e))
 
 
-@command(str, privileged=True, whole_msg=True, give_name=True, aliases=["close", "reject-force", "close-force"])
+@command(str, privileged=True, whole_msg=True, give_name=True, aliases=["close",
+                                                                        "reject-force",
+                                                                        "close-force",
+                                                                        "reject-duplicate",
+                                                                        "close-duplicate"])
 def reject(msg, args, alias_used="reject"):
     argsraw = args.split(' "', 1)
     try:
@@ -717,6 +721,7 @@ def reject(msg, args, alias_used="reject"):
     except IndexError:
         reason = ''
     force = alias_used.split("-")[-1] == "force"
+    duplicate = alias_used.split("-")[-1] == "duplicate"
     code_permissions = is_code_privileged(msg._client.host, msg.owner.id)
     self_reject = False
     try:
@@ -736,8 +741,8 @@ def reject(msg, args, alias_used="reject"):
     rejected_image = "https://img.shields.io/badge/blacklisters-rejected-red"
     message_url = "https://chat.{}/transcript/{}?m={}".format(msg._client.host, msg.room.id, msg.id)
     chat_user_profile_link = "https://chat.{}/users/{}".format(msg._client.host, msg.owner.id)
-    rejected_by_text = "[Rejected]({}) by [{}]({}) in {}.".format(message_url, msg.owner.name,
-                                                                  chat_user_profile_link, msg.room.name)
+    rejected_by_text = ("[Rejected]({})" + (" as a duplicate" if duplicate else "") + " by [{}]({}) in {}.").format(
+        message_url, msg.owner.name, chat_user_profile_link, msg.room.name)
     if self_reject:
         rejected_by_text = "[Self-rejected]({}) by [{}]({}) in {}.".format(message_url, msg.owner.name,
                                                                            chat_user_profile_link, msg.room.name)
@@ -749,7 +754,7 @@ def reject(msg, args, alias_used="reject"):
         reject_reason_image_text = ""
     comment = rejected_by_text + reject_reason_text + reject_reason_image_text
     try:
-        message = GitManager.reject_pull_request(pr_id, comment, self_reject)
+        message = GitManager.reject_pull_request(pr_id, comment, self_reject, duplicate)
         return message
     except Exception as e:
         raise CmdException(str(e))
diff --git a/gitmanager.py b/gitmanager.py
index 659adc9171..1225f7ba6c 100644
--- a/gitmanager.py
+++ b/gitmanager.py
@@ -72,6 +72,13 @@ def comment_on_thread(cls, thread_id, body):
         response = requests.post(url, data=payload, timeout=GlobalVars.default_requests_timeout, **cls.auth_args)
         return response.json()
 
+    @classmethod
+    def label_issue(cls, issue_id, labels: list):
+        url = "https://api.github.com/repos/{}/issues/{}/labels".format(GlobalVars.bot_repo_slug, issue_id)
+        payload = json.dumps({'labels': labels})
+        response = requests.post(url, data=payload, timeout=GlobalVars.default_requests_timeout, **cls.auth_args)
+        return response.json()
+
     @classmethod
     def get_pull_request(cls, pr_id, payload=""):
         """ Get pull requests info. """
@@ -380,7 +387,7 @@ def merge_pull_request(cls, pr_id, comment=""):
             cls.gitmanager_lock.release()
 
     @classmethod
-    def reject_pull_request(cls, pr_id, comment="", self_reject=False):
+    def reject_pull_request(cls, pr_id, comment="", self_reject=False, is_duplicate=False):
         response = requests.get("https://api.github.com/repos/{}/pulls/{}".format(GlobalVars.bot_repo_slug, pr_id),
                                 timeout=GlobalVars.default_requests_timeout)
         if not response:
@@ -396,6 +403,8 @@ def reject_pull_request(cls, pr_id, comment="", self_reject=False):
 
         if comment:  # yay we have comments now
             GitHubManager.comment_on_thread(pr_id, comment)
+        if is_duplicate:
+            GitHubManager.label_issue(pr_id, ["type: duplicate"])
 
         with cls.gitmanager_lock:
             origin_or_auth = cls.get_origin_or_auth()
@@ -405,11 +414,13 @@ def reject_pull_request(cls, pr_id, comment="", self_reject=False):
             if response:
                 if response.json()["state"] == "closed":
                     git.push('-d', origin_or_auth, ref)
+                    return ("Closed pull request [#{0}](https://github.com/{1}/pull/{0})" +
+                            (" as a duplicate." if is_duplicate else ".")).format(pr_id, GlobalVars.bot_repo_slug)
                     if self_reject:
                         return "You self-closed pull request [#{0}](https://github.com/{1}/pull/{0}).".format(
                             pr_id, GlobalVars.bot_repo_slug)
-                    return "Closed pull request [#{0}](https://github.com/{1}/pull/{0}).".format(
-                        pr_id, GlobalVars.bot_repo_slug)
+                    return ("Closed pull request [#{0}](https://github.com/{1}/pull/{0})" +
+                            (" as a duplicate." if is_duplicate else ".")).format(pr_id, GlobalVars.bot_repo_slug)
 
         raise RuntimeError("Closing pull request #{} failed. Manual operations required.".format(pr_id))