The Maybach Mb IVa was a water-cooled aircraft and airship straight-six engine developed in Germany during World War I by Maybach-Motorenbau GmbH, a subsidiary of Zeppelin.

Like all engines of that time, the previous Maybach design, the Mb IV, lost as much as half of the nominal power of 240 horsepower at high altitude.

The new Maybach Mb IVa of 1916 was the first engine designed to overcome this limitation.

The engine had purposely "oversized" cylinders, and a significantly higher 6.08:1 compression ratio.

[3] This would theoretically correspond to rating of about 300 hp at sea level; however, the engine was not designed to withstand such power[4] - it needed to be carefully throttled down at low altitude, so it would not exceed the safe level of 245 hp.