Tonawanda Engine is a General Motors engine factory in Buffalo, New York.

The plant consists of three facilities totaling 3.1 million square feet (290,000 m2) and sits upon 190 acres (77 ha).

The factory receives cast engine blocks from Defiance Foundry in Defiance, Ohio and Saginaw Metal Casting Operations in Saginaw, Michigan, and received engine block castings and cylinder heads from the former Massena Castings Plant in Massena, New York.

The campus houses three different engine plants.

Plant #1, located at 2995 River Road in Buffalo, was built in 1938; Plant #4, located at 2390 Kenmore Avenue, was built in 1941; and Plant #5, located at 240 Vulcan Street, was built in 2001.