The Common Gull or Mew Gull (Larus canus) is a medium-sized gull which breeds in northern Asia, northern Europe and northwestern North America. It migrates further south in winter.

Adults are 40-46 cm long, obviously smaller than the Herring Gull, and slightly smaller than the Ring-billed Gull, also differing from this in its shorter, more tapered bill with a more greenish shade of yellow, as well as being unmarked during the breeding season. The body is grey above and white below. The legs are greenish-yellow. In winter, the head is streaked grey, and the bill often has a poorly-defined blackish band near the tip (sometimes sufficiently obvious to cause confusion with Ring-billed Gull). They have black wingtips with large white "mirrors". Young birds have scaly black-brown upperparts and a neat wing pattern, and grey legs. They take two to three years to reach maturity. The call is a high-pitched "laughing" cry.

There are four subspecies, two of them considered distinct species by some authorities:

Larus canus canus Linnaeus, 1758. Common Gull. Europe and western Asia. Small; mantle medium grey (palest subspecies); wingtips with extensive black; iris dark. Wingspan 110-125 cm; weight 290-480 g.

Larus canus heinei Homeyer, 1853. Central northern Asia. Medium size; mantle dark grey (darkest subspecies); wingtips with extensive black; iris dark. Weight 315-550 g.

Larus canus kamtschatschensis (Bonaparte, 1857); syn. L. kamtschatschensis. "Kamchatka Gull". Northeastern Asia. Large; mantle medium-dark grey; wingtips with extensive black; iris pale. Weight 394-586 g.

Larus canus brachyrhynchus Richardson, 1831; syn. L. brachyrhynchus. Mew Gull or "Short-billed Gull". Alaska and western Canada. Small; mantle medium-dark grey; wingtips with little black and much white; iris pale. Wingspan 96-102 cm; weight 320-550 g.

Both Common and Mew Gulls breed colonially near water or in marshes, making a lined nest on the ground or in a small tree; colony size varies from two to 320 or more pairs. Usually three eggs are laid (sometimes just one or two); they hatch after 24-26 days, with the chicks fledging after a further 30-35 days. Like most gulls, they are omnivores and will scavenge as well as hunt small prey. The global population is estimated to be about one million pairs; they are most numerous in Europe, with over half (possibly as much as 80-90%) of the world population. By contrast, the Alaskan population is only about 10,000 pairs.

The Common Gull occurs as a scarce winter visitor to coastal eastern Canada and as a vagrant to the northeastern USA, and there is one recent record of Mew Gull in Europe on the Azores.