A delivery van stops outside. Your dog is at the glass before you hear the engine. The van leaves, and the barking seems to have worked. Tomorrow, the same scene plays again.
Your dog might be startled, excited, frustrated by the glass, or worried about a stranger. You cannot tell which from the bark alone. What you can change today is how often your dog rehearses that dash to the window.
First, change the window
Try closing the blinds, using removable privacy film on the lower panes, or moving the dog's resting spot away from the view. If your dog barks at sounds as well as sights, a quieter room may help more than a window covering. This is not giving up on training. It gives both of you a calmer place to start.
Notice the pattern for a couple of days: people, dogs, vehicles, or the sound of the letterbox? Keep the note simple. A dog that watches calmly does not need every window covered, a dog that spends the day scanning and barking may benefit from a lasting change to the view.
Teach a different ending
When you can be there to practice, start with an easy view, not the busiest hour on the street. Sit a little back from the window with a mat and small treats. When your dog spots something outside and is still able to turn toward you, calmly offer a treat. Feed while the thing passes. If your dog chooses to look back at you or moves to the mat, reward that too. A short practice that ends before barking is more useful than waiting for the loudest moment to test a cue.
Outside practice, keep the view blocked. If barking starts, avoid shouting over it or dragging the dog from the glass. Call them toward an easier spot if they can respond, and make the view less available next time. If they cannot disengage, today's setup was too hard. Try a calmer time or a more distant room rather than asking for more self-control in the same situation.
Some dogs need a cue like "go to your mat" taught separately, away from the window, before it can help here. Reward the trip to the mat often when nothing is happening outside. Then, with practice, the noise at the window can become a reason to move toward you instead of launching forward.
If the behavior is sudden, extreme, or comes with growling or attempts to break through the glass, speak with your veterinarian and a qualified, reward-based behavior professional. Safety comes before a training exercise. For more on helping your dog notice triggers without rehearsing a rush, see the barking and reactivity guide, blocking the view when needed is still useful
Sources: American Kennel Club: Does Your Dog Bark Out the Window? (updated June 2026). Best Friends Animal Society: How to Use Visual Barriers for Dog Reactivity and Fence Running.