10 Common Dog Idioms That Native Speakers use (Real Examples)

Learn 10 common dog idioms that I have taught to my private English students here in Japan. For each idiom, I’ll break down the meaning and give you real examples that you can use in your own English conversations.

I updated this post from an earlier blog. 2018 was the Year of the Dog according to the Chinese zodiac.

Let sleeping dogs lie

This expression is used to advise against actions that might cause problems. If things are fine right now, we shouldn’t change them if we think there is a danger that things may become worse.
The idea is that if a dog is sleeping and we wake him up, he may become angry. It’s better to just let him sleep.

  • Jill: “Should I ask the boss if he’s upset with me? I came in late this morning?”
    Jane: “If he hasn’t said anything to you, I wouldn’t mention it. Maybe he didn’t notice. Just let sleeping dogs lie.”
    = If the boss didn’t say anything you shouldn’t mention it, there is no need to mention it.
Dog Idioms - let sleeping dogs lie

You can’t teach an old dog new tricks

This idiom means it is difficult to make someone change the way they do something. Especially when they have been doing it the same way for a long time.
It is much more difficult to teach an older dog than it is to teach a puppy.

  • Do you want to teach your grandfather to use a computer? He is 84. You can’t teach an old dog new tricks, you know.
    = It will be hard to teach your 84-year-old grandfather how to use a computer.

A movie review quote for the new Tom Cruise movie Top Gun: Maverick.

You can’t teach an old dog new tricks. But Top Gun: Maverick is going to ask an old dog to teach some new recruits.


Every dog has its day

This idiom means that everyone will get a chance to do something at some time – OR – have an opportunity to be great.
It comes from a time when dogs were thought of as very low animals.
But even though you are low now, you will have a chance to do something great someday, even for only one day.

  • You didn’t make the soccer team this season but keep practicing. Every dog has its day.
    = Keep trying and your chance to make the soccer team will come.
  • I lost my tennis match today but I’ll have another chance next month and every dog has its day. I will show everyone how good I am.

Barking up the wrong tree

This expression is used when someone has the wrong idea and they are wasting their time.
Dogs often like to chase cats or other animals that will run up a tree for safety. If the animal escapes from the tree but the dog doesn’t realize it, he keeps barking even though the tree is empty.
We say he is barking up the wrong tree. His idea is not correct, he is wasting his time.

  • Hector had nothing to do with the robbery – the police are really barking up the wrong tree this time.
    = I think the police are wasting their time with Hector. He didn’t do it.
  • Diane has a boyfriend. You could ask her out but I think you’re barking up the wrong tree.
    = It’s a waste of time to ask her out because she already has a boyfriend.
Dog Idioms - Barking up the wrong tree

Work like a dog

This expression means to work very very hard.
It comes from a time when dogs were work animals that had a job to do. They weren’t just pets and they had to work very hard to earn their food.

  • My team at the office worked like dogs all December to prepare our year-end report. We are all so tired!
  • It’s been a hard month, I have been working like a dog.

This chorus of the popular Beatle’s song “A Hard Day’s Night” is:
It’s been a hard day’s night, and I’ve been working like a dog.
It’s been a hard day’s night, I should be sleeping like a log.

Sick as a dog

  • Last Friday I had to cancel my dentist appointment because I felt terrible. I had a headache and an upset stomach. I was sick as a dog.

Can you guess what the expression “sick as a dog” means? If you are sick as a dog you are very ill.

  • Jonathan drank too much at the party last night and today he’s sick as a dog!
Dog Idioms - Sick as a dog

Someone’s bark is worse than their bite

If someone’s bark is worse than their bite it means they talk tough but they’re actually not. They act dangerous but their words are stronger than their actions. 

  • The Prime Minister talks tough but he gets pushed around by other leaders all the time. Unfortunately, his bark is worse than his bite. I wish you would be more forceful, especially when dealing with bigger countries. 
  • The boxer talked a lot to reporters about how he was going to dominate the fight. On Fight Night he was knocked out in the fourth round, it seems like his bark was much worse than his bite.

(BE) in the doghouse

We say that a person is in the doghouse if they’ve done something to displease another person, especially someone they are close to

  • My wife is really mad at me. I came home late last night because I went drinking with my friends after work. I missed the nice dinner she prepared for us. I’m in the doghouse now.
    = My wife is not happy with me right now.

Puppy dog eyes

If someone looks at you with puppy dog eyes they want your attention or your affection. Puppies have large round eyes that can cause us to desire to pet or feed them. We want to give them our attention and affection.

  • I can’t say no to my daughter when she looks at me with those puppy dog eyes.


An underdog is a person, team, country, etc. that is considered to be weaker and less likely to be successful or win a competition. 

This term comes from the 1800s when dog fights were common in parts of the world. The dog who lost the fight would be called the underdog. 

  • I don’t often gamble but when I bet on sports I always bet on the underdog. The payout is much higher if they win.
    = I bet money on the team that is less likely to win.
  • She was a  popular politician who always fought for the underdogs
    = The politician always took care of the people who needed help, people who are not so successful

Thanks for reading my Idioms with Dog blog post. Leave a comment at the bottom of this post if it was helpful for you!

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