The Kvarner Gulf (Croatian: Kvarnerski zaljev),^[1] sometimes also Kvarner Bay, is a bay in the northern Adriatic Sea, located between the Istrian peninsula and the northern Croatian Littoral mainland. The bay is a part of Croatia's internal waters.

The largest islands within the Kvarner are Cres, Krk, Pag, Rab and Lošinj. A portion of the Kvarner Bay, located between Cres, Krk, Rab and Pag is also called Kvarnerić (literally "little Kvarner"; Italian: Golfo del Quarnerolo or Carnerolo), and the portion east of Krk and Rab is called Senj Channel (after the mainland town of Senj).

The bay is notable for its depth (more than 100 meters), which allows for the city of Rijeka at its northernmost point to have a sea port that can accommodate Capesize ships.^[2]

The bay is also home to many beaches and tourist locations because of its beautiful waters and warm climate.