321 (Netherlands) Squadron RAF was a unit of the Royal Air Force during the Second World War formed from the personnel of the Marineluchtvaartdienst (MLD), the Royal Netherlands Naval Air Service.

It was equipped with Consolidated Catalinas, which were crewed by MLD personnel who escaped to Ceylon.

The squadron's headquarters was located at RAF China Bay with detachments based in Mombasa, Cocos Islands, Socotra, Masirah, Ceylon, Durban, Port Elizabeth, Aden and Cape Town.

Supplemented with Consolidated Liberators in July 1945, the air echelon moved to Cocos Island in preparation for Operation Zipper, the proposed invasion of Malaya.

Along with 320 Squadron, it flew maritime patrol missions from Valkenburg for decades afterwards.