The Subaru EA engine is a series of automobile internal combustion engines manufactured by Subaru, a division of Fuji Heavy Industries. All EA series engines are of a flat-4 design, and have always been water cooled.

Prior to 1966, Subaru was known for producing kei cars in Japan; for their first four-passenger model, the firm developed an air-cooled boxer engine for a prototype of the Subaru 1500 in 1960, but Fuji Heavy Industries was unable to continue development due to a shortage of funding. A new prototype front-wheel-drive car was built with a 923 cc (56 cu in) water-cooled boxer engine, which became the basis for the Subaru 1000 and the EA-52 boxer engine. The car began sales to the public starting in 1966.

The EA series engines have aluminum heads with aluminum blocks. Each cylinder has two valves, one for exhaust and one for intake. They came in either an OHV pushrod or SOHC configuration. The engine was very short, only about 400 mm (15.7 in) long overall. The crankshaft had three main bearings.

Subaru produced the EA series from 1966 to 1994, and were found in the Subaru FF-1 Star, the Subaru Leone, the Subaru Brat (Brumby), the Subaru Loyale, the Subaru Omega (coupé), the Subaru Vortex, the Subaru RX, and the Subaru XT (Alcyone).

The Subaru EA-52 engine was produced from 1966 until 1970.

The Subaru EA-53 was used in the 1967 Subaru 1000 Sports Sedan, sold in Japan. It used twin carburetors. This engine was used in the September 1968 Japan Alpine Rally which the car won in the 1000cc engine class.

The Subaru EA-61 engine was produced from 1969 to 1972. The Japanese-spec Subaru FF-1 Sport Sedan and the FF-1 Super Touring sedan used twin carburetors, with the engine designation EA-61S. It was sold in the United States only for the 1971 model year. It was also briefly available in the first Leone, only in 1100 Van specification.

The Subaru EA-62 engine was produced from 1971 to 1972. It is the only EA-series engine with rear-facing exhaust ports.