The Wellesley Islands are a group of islands off the coast of north Queensland, Australia, in the Gulf of Carpentaria. They were named by Matthew Flinders in honour of Richard Wellesley, 1st Marquess Wellesley. The largest island in the group is Mornington Island. Two small islands in the group form the Manowar and Rocky Islands Important Bird Area because of their importance for breeding seabirds.