diff --git a/sopel/coretasks.py b/sopel/coretasks.py
index 5fe5d026ff..74c17ec4c6 100644
--- a/sopel/coretasks.py
+++ b/sopel/coretasks.py
@@ -311,7 +311,9 @@ def startup(bot, trigger):
 @plugin.priority('medium')
 def handle_isupport(bot, trigger):
     """Handle ``RPL_ISUPPORT`` events."""
-    # remember if NAMESX is known to be supported, before parsing RPL_ISUPPORT
+    # remember if certain actionable tokens are known to be supported,
+    # before parsing RPL_ISUPPORT
+    botmode_support = 'BOT' in bot.isupport
     namesx_support = 'NAMESX' in bot.isupport
 
     # parse ISUPPORT message from server
@@ -326,6 +328,12 @@ def handle_isupport(bot, trigger):
 
     bot._isupport = bot._isupport.apply(**parameters)
 
+    # was BOT mode support status updated?
+    if not botmode_support and 'BOT' in bot.isupport:
+        # yes it was! set our mode unless the config overrides it
+        botmode = bot.isupport['BOT']
+        if botmode not in bot.config.core.modes:
+            bot.write(('MODE', bot.nick, '+' + botmode))
     # was NAMESX support status updated?
     if not namesx_support and 'NAMESX' in bot.isupport:
         # yes it was!
diff --git a/test/test_coretasks.py b/test/test_coretasks.py
index 9dc2ee0e2a..49d39408a6 100644
--- a/test/test_coretasks.py
+++ b/test/test_coretasks.py
@@ -278,6 +278,51 @@ def test_handle_isupport(mockbot):
     assert 'CNOTICE' in mockbot.isupport
 
 
+@pytest.mark.parametrize('modes', ['', 'Rw'])
+def test_handle_isupport_bot_mode(mockbot, modes):
+    mockbot.config.core.modes = modes
+
+    mockbot.on_message(
+        ':irc.example.com 005 Sopel '
+        'SAFELIST ELIST=CTU CPRIVMSG CNOTICE '
+        ':are supported by this server')
+
+    assert 'BOT' not in mockbot.isupport
+    assert mockbot.backend.message_sent == []
+
+    mockbot.on_message(
+        ':irc.example.com 005 Sopel '
+        'BOT=B '
+        ':are supported by this server')
+
+    assert 'BOT' in mockbot.isupport
+    assert mockbot.isupport['BOT'] == 'B'
+    assert mockbot.backend.message_sent == rawlist('MODE TestBot +B')
+
+    mockbot.on_message(
+        ':irc.example.com 005 Sopel '
+        'BOT=B '
+        ':are supported by this server')
+
+    assert len(mockbot.backend.message_sent) == 1, 'No need to resend!'
+
+
+@pytest.mark.parametrize('modes', ['B', 'RBw'])
+def test_handle_isupport_bot_mode_override(mockbot, modes):
+    mockbot.config.core.modes = modes
+
+    mockbot.on_message(
+        ':irc.example.com 005 Sopel '
+        'BOT=B '
+        ':are supported by this server')
+
+    assert 'BOT' in mockbot.isupport
+    assert mockbot.isupport['BOT'] == 'B'
+    assert mockbot.backend.message_sent == [], (
+        'Bot should not set mode overridden by config setting'
+    )
+
+
 def test_handle_isupport_namesx(mockbot):
     mockbot.on_message(
         ':irc.example.com 005 Sopel '