Mehmet Ali Aybar (pronounced [mehmet aɫi ajbaɾ]; 5 October 1908 – 10 July 1995) was a lawyer, member of the Turkish parliament, the second president of the Workers Party of Turkey (Turkish: Türkiye İşçi Partisi or briefly TİP), the founder and President of the Socialist Revolution Party, and a member of the Russell Tribunal against the war crimes of the United States in Vietnam.

Aybar's father was Tahsin Bey, who was the son of Hüseyin Hüsnü Pasha, first commander of the Action Army.

[1] His writings for the Istanbul magazine Hür (Free) engendered anger on the part of the government and he was briefly imprisoned.

[5] Aybar personally opposed the Soviet Union's invasion of Czechoslovakia and this caused disputes in the party.

[8] Aybar was also a member of the International War Crimes Tribunal which was founded by Bertrand Russell.