Mason Street Schoolhouse is a historical building in San Diego, California, built in 1865.

For some time in the 1940s to 1952, the schoolhouse was a tamale restaurant, which operated out of the building until 1952.

In 1952, the San Diego County Historical Days Association acquired the schoolhouse, and it was restored in 1955.

The first teacher was Mary Chase Walker (1828–1899) born in Massachusetts.

Walker had 35 students of ages 4 to 17 in the single one-room schoolhouse.