Gottlieb Jaan Ast (2 March 1874 – 15 December 1919) was an Estonian politician who was the mayor of Tallinn from June to July 1919.

Afterwards, he became involved in politics and was active in southern Estonia as a socialist agitator.

[1] After returning to Estonia, he joined the Estonian Social Democratic Workers' Party and was elected as a representative of the party to the Tallinn City Government and was later the mayor of Tallinn, where he served for one month, from June to July 1919.

He died of tuberculosis in December 1919 and was buried in Rahumäe cemetery.

[2] His younger brother was politician and writer Karl Ast.