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 ad4f05fe6b..a30415c435 100644
--- a/transport/src/main/java/io/netty/channel/nio/AbstractNioChannel.java
+++ b/transport/src/main/java/io/netty/channel/nio/AbstractNioChannel.java
@@ -240,7 +240,11 @@ public abstract class AbstractNioChannel extends AbstractChannel {
                 connectPromise.setFailure(t);
                 closeIfClosed();
             } finally {
-                connectTimeoutFuture.cancel(false);
+                // Check for null as the connectTimeoutFuture is only created if a connectTimeoutMillis > 0 is used
+                // See https://github.com/netty/netty/issues/1770
+                if (connectTimeoutFuture != null) {
+                    connectTimeoutFuture.cancel(false);
+                }
                 connectPromise = null;
             }
         }