The Vega gull, East Siberian gull, or East Siberian herring gull (Larus vegae) is a large gull of the herring gull/lesser black-backed gull complex which breeds in North-east Asia. Its classification is still controversial and uncertain. It is variously treated as a separate species, as a subspecies of American herring gull (L. smithsonianus) or included with both the American herring gull and European herring gull in L. argentatus. The Mongolian gull, Larus mongolicus, has previously been regarded as a subspecies of the Caspian gull (L. cachinnans) but is now sometimes lumped with the Vega gull.