English Idioms About Dogs

There are tons and tons of idioms in the English language about dogs, but here are 5 of our favorites!

The Dog Days of Summer

Happy Summer! In honor of the start of summer, we want to talk about the idiom dog days of summer. The expression the dog days of summer is used to describe the hottest days of summertime. 


During the dog days of summer, you can either find me at the beach, or inside my air conditioned house! It's way too hot to do anything else.

It is recommended that you drink a lot of water and stay cool during the dog days of summer to aoid heatstroke.

Once the dog days of summer hit, many people take s vacation to the mountains where it is cooler.

Barking Up the Wrong Tree

We use the expression barking up the wrong tree if someone is making a wrong choice, pursuing the wrong thing, or making a false assumption about someone. 

You might have seen dogs chasing animals, such as squirrels or rabbits. The squirrels often run up one tree to escape, and then jump to another tree once it's high enough. The dog might not notice this, and continue barking up the wrong tree without realizing that his prey has moved to a different tree!


Nicholas asked me to help him cheat on the test. I told him, no way, you're barking up the wrong tree! I'm an honest student and I don't want to get kicked out of school.

I accused my dog of destroying the couch, but I realized I was barking up the wrong tree when I saw pieces of the couch pillows in my cats hair!

Rick had been flirting with Jodi all night, but realized he was barking up the wrong tree because she actually had a crush on his best friend.

Can’t Teach an Old Dog New Tricks

Have you ever heard the idiom, you can’t teach an old dog new tricks? We use this to describe someone who is not open to change or improvement. This kind of person usually doesn’t want to learn a better way to do something and is very stubborn, so we are comparing them to an "old dog" who doesn't want to learn "new tricks"! 🐶

In contrast, some people say "you're never too old to learn!" Which expression do you agree the most with?


Mr. Gonzalez had been taking attendance on paper for 30 years and he refused to start using a computer. Like they say, you can’t teach an old dog new tricks.

We tried to teach our grandmother how to use her iPhone, but it was nearly impossible! I guess you really can’t teach an old dog new tricks.

Let Sleeping Dogs Lie

Let sleeping dogs lie, which means that you should not bring up old fights or conflicts. Instead, it is best to just forget them and let them be. This is especially common if an argument has been dropped, but not resolved. Letting sleeping dogs lie is a way of keeping the peace and avoiding conflict.


My sister was wearing the shirt that I know she stole from me, but we were having a peaceful family dinner so I decided to just let sleeping dogs lie and not bring it up.

Hannah got her test back and noticed that the teacher made a mistake on her grade. She was getting an A in the class anyway, so she decided to let sleeping dogs lie and not bother asking the teacher to correct it.

Alex knew that him and his girlfriend would never come to an agreement about whose turn it was to do the dishes, so he thought it was best to let sleeping dogs lie and just do them himself.

Sick as a Dog

Today's idiom is sick as a dog. This expression actually dates back to the 1700s when there weren't many veterinarians to help sick dogs, so it was common for dogs to be very sick. Now, if someone is very, very ill, we say that they are "sick as a dog." 🐶😷 


Rebecca ate a bad hamburger and got food poisoning. Her boss said to her, "Rebecca, you look as sick as a dog, you need to go home right now!"

Jennifer was very tired while traveling in Costa Rica. She thought she was just homesick, but realized she was running a fever. She finally admitted that she was sick as a dog and went to the hospital. 🤒

I don't know what was in that seafood dinner, but afterwards, everyone in my family was sick as a dog!

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