Lars Gabriel von Haartman (23 September 1789 Turku - 16 December 1859 Merimasku) was a Swedish-speaking Finnish politician.

Along with Count Gustaf Mauritz Armfelt, he was one of the most prominent politicians who were in favour of developing Finland as part of the Russian Empire instead of striving towards independence.

Being a representative of the Turku Academy in St. Petersburg, Gabriel Haartman made a great influence on his son's future.

Lars joined Ministry of foreign affairs of Russia at a young age, and already in 1811 he became an official of the committee on Finnish Affairs and Secretary to the chancellor of the Turku Academy, and remained in St. Petersburg until 1827.

During two years (1827-1829) he made a trip to Sweden, Denmark, Northern Italy, the Netherlands, Belgium, France and England.