The Treaty of Rapallo was a treaty between Italy and the Kingdom of Serbs, Croats and Slovenes by which the latter was forced to give up parts of its Slovenian and Croatian territory.

The territory given up comprised Istria, the city of Zadar and islands of Cres, Lošinj, Lastovo and Palagruža, some of which contained substantial Italian populations.

The treaty ceased to be effective on April 6, 1941 when Italy invaded the Kingdom of Yugoslavia so much of this territory was later returned to Yugoslavia following World War II.