diff --git a/transport-native-epoll/src/main/java/io/netty/channel/epoll/AbstractEpollChannel.java b/transport-native-epoll/src/main/java/io/netty/channel/epoll/AbstractEpollChannel.java
index 8e0515303a..4a53a8dbac 100644
--- a/transport-native-epoll/src/main/java/io/netty/channel/epoll/AbstractEpollChannel.java
+++ b/transport-native-epoll/src/main/java/io/netty/channel/epoll/AbstractEpollChannel.java
@@ -31,6 +31,7 @@ import io.netty.channel.ChannelPromise;
 import io.netty.channel.ConnectTimeoutException;
 import io.netty.channel.EventLoop;
 import io.netty.channel.RecvByteBufAllocator;
+import io.netty.channel.nio.AbstractNioChannel;
 import io.netty.channel.socket.ChannelInputShutdownEvent;
 import io.netty.channel.socket.ChannelInputShutdownReadComplete;
 import io.netty.channel.socket.SocketChannelConfig;
@@ -572,9 +573,9 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
                             @Override
                             public void run() {
                                 ChannelPromise connectPromise = AbstractEpollChannel.this.connectPromise;
-                                ConnectTimeoutException cause =
-                                        new ConnectTimeoutException("connection timed out: " + remoteAddress);
-                                if (connectPromise != null && connectPromise.tryFailure(cause)) {
+                                if (connectPromise != null && !connectPromise.isDone()
+                                        && connectPromise.tryFailure(new ConnectTimeoutException(
+                                        "connection timed out: " + remoteAddress))) {
                                     close(voidPromise());
                                 }
                             }
diff --git a/transport-native-kqueue/src/main/java/io/netty/channel/kqueue/AbstractKQueueChannel.java b/transport-native-kqueue/src/main/java/io/netty/channel/kqueue/AbstractKQueueChannel.java
index 02d2a1c28d..d5c221ffa4 100644
--- a/transport-native-kqueue/src/main/java/io/netty/channel/kqueue/AbstractKQueueChannel.java
+++ b/transport-native-kqueue/src/main/java/io/netty/channel/kqueue/AbstractKQueueChannel.java
@@ -31,6 +31,7 @@ import io.netty.channel.ChannelPromise;
 import io.netty.channel.ConnectTimeoutException;
 import io.netty.channel.EventLoop;
 import io.netty.channel.RecvByteBufAllocator;
+import io.netty.channel.nio.AbstractNioChannel;
 import io.netty.channel.socket.ChannelInputShutdownEvent;
 import io.netty.channel.socket.ChannelInputShutdownReadComplete;
 import io.netty.channel.socket.SocketChannelConfig;
@@ -558,9 +559,9 @@ abstract class AbstractKQueueChannel extends AbstractChannel implements UnixChan
                             @Override
                             public void run() {
                                 ChannelPromise connectPromise = AbstractKQueueChannel.this.connectPromise;
-                                ConnectTimeoutException cause =
-                                        new ConnectTimeoutException("connection timed out: " + remoteAddress);
-                                if (connectPromise != null && connectPromise.tryFailure(cause)) {
+                                if (connectPromise != null && !connectPromise.isDone()
+                                        && connectPromise.tryFailure(new ConnectTimeoutException(
+                                        "connection timed out: " + remoteAddress))) {
                                     close(voidPromise());
                                 }
                             }
diff --git a/transport/src/main/java/io/netty/channel/nio/AbstractNioChannel.java b/transport/src/main/java/io/netty/channel/nio/AbstractNioChannel.java
index a1c4520344..2db6b7c6ee 100644
--- a/transport/src/main/java/io/netty/channel/nio/AbstractNioChannel.java
+++ b/transport/src/main/java/io/netty/channel/nio/AbstractNioChannel.java
@@ -258,9 +258,9 @@ public abstract class AbstractNioChannel extends AbstractChannel {
                             @Override
                             public void run() {
                                 ChannelPromise connectPromise = AbstractNioChannel.this.connectPromise;
-                                ConnectTimeoutException cause =
-                                        new ConnectTimeoutException("connection timed out: " + remoteAddress);
-                                if (connectPromise != null && connectPromise.tryFailure(cause)) {
+                                if (connectPromise != null && !connectPromise.isDone()
+                                        && connectPromise.tryFailure(new ConnectTimeoutException(
+                                                "connection timed out: " + remoteAddress))) {
                                     close(voidPromise());
                                 }
                             }