The Continental IO-550 engine is a large family of 9 liter fuel injected six-cylinder, horizontally opposed, air-cooled aircraft engines that were developed for use in light aircraft by Teledyne Continental Motors.

[1][2] The IOF-550 is an Aerosance FADEC equipped version of the same basic engine, the TSIO-550 is a dual turbocharged version and the TSIOL-550 is a liquid-cooled variant.

[1][2][3] There is no O-550 engine, which would be a carburetor-equipped variant, hence the base model is the IO-550.

[1][2] This engine family competes with the Lycoming IO-580 series which are also six-cylinder engines with similar power output and weight.

[1][2] The engines were first developed in the early 1980s and first certified on a regulatory basis of FAR 33, 1 February 1965 amendment, 33-8, 2 May 1977.