Babolsar (Persian: بابلسر, also Romanized as Bābolsar and Bābul Sar; also known as Mashhadsar (Persian: مَشهَدسَر), also Romanized as Mashhad-i-Sar and Meshed-i-Sar) is a city and capital of Babolsar County, Mazandaran Province, Iran. It is located alongside the Caspian Sea.
At the 2016 census, the city population was 75,761, in 24,666 families.