diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2e262f2a1..53d8bf0a4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ SPDX-License-Identifier: GPL-3.0-or-later
 
 - core: fix buffer size in function util_parse_time, causing buffer overflow error in unit tests
 - irc: fix creation of irc.msgbuffer option without a server name
+- irc: ignore self join if the channel is already joined ([#2291](https://github.com/weechat/weechat/issues/2291))
 
 ## Version 4.8.1 (2025-12-01)
 
diff --git a/src/plugins/irc/irc-protocol.c b/src/plugins/irc/irc-protocol.c
index 539f347ad..9ac0882b8 100644
--- a/src/plugins/irc/irc-protocol.c
+++ b/src/plugins/irc/irc-protocol.c
@@ -1753,6 +1753,9 @@ IRC_PROTOCOL_CALLBACK(join)
     ptr_channel = irc_channel_search (ctxt->server, ctxt->params[0]);
     if (ptr_channel)
     {
+        /* ignore self join if the channel is already joined */
+        if (ctxt->nick_is_me && ptr_channel->nicks)
+            return WEECHAT_RC_OK;
         ptr_channel->part = 0;
     }
     else
diff --git a/tests/unit/plugins/irc/test-irc-protocol.cpp b/tests/unit/plugins/irc/test-irc-protocol.cpp
index f1d08089c..810221437 100644
--- a/tests/unit/plugins/irc/test-irc-protocol.cpp
+++ b/tests/unit/plugins/irc/test-irc-protocol.cpp
@@ -2070,7 +2070,6 @@ TEST(IrcProtocolWithServer, join)
     LONGS_EQUAL(0, ptr_channel->has_quit_server);
     LONGS_EQUAL(0, ptr_channel->cycle);
     LONGS_EQUAL(0, ptr_channel->part);
-    LONGS_EQUAL(0, ptr_channel->part);
     STRCMP_EQUAL(NULL, ptr_channel->pv_remote_nick_color);
     POINTERS_EQUAL(NULL, ptr_channel->hook_autorejoin);
 
@@ -2090,6 +2089,10 @@ TEST(IrcProtocolWithServer, join)
 
     CHECK(ptr_channel->buffer);
 
+    /* second self JOIN should be ignored if already joined */
+    RECV(":alice!user@host JOIN #test ");
+    CHECK_NO_MSG;
+
     RECV(":bob!user@host JOIN #test  *  :   ");
     CHECK_CHAN("-->", "bob (   ) (user@host) has joined #test",
                "irc_join,irc_smart_filter,nick_bob,host_user@host,log4");