diff --git a/lib/net/imap.rb b/lib/net/imap.rb
index 3bd776fc..a9965aec 100644
--- a/lib/net/imap.rb
+++ b/lib/net/imap.rb
@@ -3702,7 +3702,7 @@ def tcp_socket(host, port)
       s = Socket.tcp(host, port, :connect_timeout => open_timeout)
       s.setsockopt(:SOL_SOCKET, :SO_KEEPALIVE, true)
       s
-    rescue Errno::ETIMEDOUT
+    rescue Errno::ETIMEDOUT, IO::TimeoutError
       raise Net::OpenTimeout, "Timeout to open TCP connection to " +
         "#{host}:#{port} (exceeds #{open_timeout} seconds)"
     end
diff --git a/test/net/imap/test_imap.rb b/test/net/imap/test_imap.rb
index 95d61c11..a35fbca7 100644
--- a/test/net/imap/test_imap.rb
+++ b/test/net/imap/test_imap.rb
@@ -62,6 +62,14 @@ class IMAPTest < Net::IMAP::TestCase
     end
   end
 
+  def test_open_timeout
+    host = ENV.fetch("TEST_OPEN_TIMEOUT_HOST", "10.255.255.1")
+    pend host if host.start_with? "skip"
+    assert_raise(Net::OpenTimeout) do
+      Net::IMAP.new(host, open_timeout: 0)
+    end
+  end
+
   def test_unexpected_eof
     server = create_tcp_server
     port = server.addr[1]