The Gulf of Riga, or Bay of Riga, is a bay of the Baltic Sea between Latvia and Estonia.

The area of the Gulf of Riga is about 18,000 km². The maximum depth is 54 m. The island of Saaremaa (Estonia) partially separates it from the rest of the Baltic Sea. The main exit out of the gulf is the Irbe Strait. Ruhnu island, in the middle of the gulf, also belongs to Estonia.

Notable cities in this gulf include Riga, Pärnu, Jūrmala and Kuressaare. The main rivers flowing into the gulf are the Daugava, the Pärnu, the Lielupe, the Gauja, and the Salaca.