The Ulla is a 132 km long river in Galicia, Spain.
Its source is sometimes given as Antas de Ulla and sometimes the neighbouring municipality of Monterroso. It flows to the Ría de Arosa estuary near the city of Catoira, Spain. Its basin is the largest in Galicia after the Minho River. Tributaries include the rivers Deza and Arnego.
