VY Canis Majoris is one of the largest known stars by radius, a red hypergiant about 1,420 times larger than our Sun. While stars like UY Scuti and Stephenson 2-18 may be larger, VY Canis Majoris was historically cited as the largest. Betelgeuse and Antares are red supergiants but smaller, while Sirius is actually a bright nearby star, not a giant.