With more than two million videos on YouTube, cats are one of the most searched for things on the internet.
A new exhibition called "How Cats Took Over The Internet" has opened at the Museum of Moving Images in New York.
The exhibition looks at the history of how they rose to internet fame, and why people like them so much.
Almost half of all original YouTube videos are of people's pets, and around 26 billion views are just for cats, making them the single most popular category.
Some cats have even become famous, and earn millions of pounds after their owners posted their pictures online.
So how did cats become so popular? Ayshah's been taking a closer look...