Ya'akov Riftin (Hebrew: יעקב ריפתין,16 March 1907 – 14 May 1978) was an Israeli politician who served as a member of the Knesset for Mapam between 1949 and 1965.

Born in Wólka Profecka near Puławy in the Russian Empire (today in Poland), Riftin joined the HaShomer youth movement, and was later a member of Hashomer Hatzair, becoming one of the leaders of the movement in Poland.

He made aliyah to Mandatory Palestine in 1929, and joined kibbutz Ein Shemer in 1931.

According to the Vasili Mitrokhin documents, Riftin regularly passed on classified documents, including top secret ones, to the Soviet Embassy.

A member of the left-wing group in Mapam, he left the party in 1968 when it formed an alliance with the Labor Party in 1968, and formed the Left Independent Socialist Zionist Union, which unsuccessfully ran in Histadrut elections.