National Mutt Day is set for Saturday, which is a day to celebrate the mixed-breed pups' outstanding qualities by adopting one, volunteering at a shelter and more. iStock/Getty Images Plus 4.

What is National Mutt Day and Why It’s Pawsitively Important National Mutt Day, also known as National Mixed Breed Dog Day, was founded in 2005 by animal welfare advocate Colleen Paige.

National Mutt Day was established in 2005 by Colleen Paige, who also created observances like National Puppy Day and National Cat Day. In 2023, more than 3.2 million dogs entered the shelter system.