There are a few reasons why your dog might show his teeth to you. One possibility is that he's trying to communicate something to you. For example, he might be trying to show you that he's happy or that he wants to play. Another possibility is that he's feeling threatened or aggressive. If your dog is showing his teeth, it's important to respond in a way that doesn't escalate the situation further. Here are some examples of different situations and ways to respond. When Your Dog Is Happy When Your Dog Wants to Play When Your Dog Is Feeling Threatened or Aggressive When You're Not Sure What Your Dog Is Trying to Tell You When Your Dog Has Been Biting Someone Else When You Can't Tell Whether Your Dog Is Friendly Or Aggressive