diff --git a/gitea/apiobject.py b/gitea/apiobject.py
index df92e54..3e533ec 100644
--- a/gitea/apiobject.py
+++ b/gitea/apiobject.py
@@ -344,6 +344,7 @@ class Repository(ApiObject):
     REPO_DELETE = """/repos/%s/%s"""  # <owner>, <reponame>
     REPO_TIMES = """/repos/%s/%s/times"""  # <owner>, <reponame>
     REPO_TOPICS = """/repos/%s/%s/topics""" # <owner, <reponame>
+    REPO_TOPIC = """/repos/%s/%s/topics/%s"""  # <owner, <reponame>, <topicname>
     REPO_USER_TIME = """/repos/%s/%s/times/%s"""  # <owner>, <reponame>, <username>
     REPO_COMMITS = "/repos/%s/%s/commits"  # <owner>, <reponame>
     REPO_TRANSFER = "/repos/{owner}/{repo}/transfer"
@@ -470,7 +471,13 @@ class Repository(ApiObject):
             Repository.REPO_TOPICS % (self.owner.username, self.name)
         )
         return results["topics"]
-        
+    
+    def add_topic(self, topic: str):
+        """Add a topic to the repository"""
+        result = self.gitea.requests_put(
+            Repository.REPO_TOPIC % (self.owner.username, self.name, topic)
+        )
+    
     def get_user_time(self, username) -> float:
         if isinstance(username, User):
             username = username.username