José Joaquín Estudillo (May 7, 1800 – June 7, 1852) was a Californio statesman and ranchero who served as the 2nd Alcalde of San Francisco (then known as Yerba Buena).

José Joaquín joined the Spanish Army himself at the age of 15 as a soldado distinguido ("distinguished soldier") at the Monterey Presidio.

[3] It is unclear when he moved to Yerba Buena, but records indicate that he was the commissioner in charge of the secularization of Mission San Francisco de Asís at the beginning of 1835.

His descendants donated the land where his house, Casa de Estudillo, stood for construction of St. Leander's Church.

That site was declared California Historical Landmark #279,[10] and sits on the street that now bears his name, Estudillo Avenue.