The BMC E-series engine is a line of straight-4 and straight-6 overhead camshaft automobile petrol engines from the British Motor Corporation (BMC). It displaced 1.5 L or 1.8 L in four-cylinder form, and 2.2 L or 2.6 L as a six-cylinder. The company's native United Kingdom market did not use the 2.6 L version, which was used in vehicles of Australian and South African manufacture. Although designed when the parent company was BMC, by the time the engine was launched the company had become British Leyland (BL), and so the engine is commonly referred to as the British Leyland E-series engine.

The inline-six engine is a piston engine with six cylinders arranged in a straight line along the crankshaft. A straight-six engine has perfect primary and secondary engine balance, resulting in fewer vibrations than other designs of six or fewer cylinders.