烯酮是含有R₂C=C=O结构的有机化合物的统称。赫尔曼·施陶丁格在烯酮研究方面作了很大贡献。最简单的烯酮是乙烯酮，分子中两个R都是氢原子。

由于积聚双键的存在，性质很活泼，易加成及聚合。

乙烯酮是无色有强烈气味的气体，刺激性和毒性很大，熔点-150.5°C(-239°F)，沸点-56.1°C(-69°F)。

A ketene is an organic compound of the form R′R″C=C=O. The term is also used specifically to mean ethenone, the simplest ketene, where R′ and R″ are hydrogen atoms.

Ketenes were first studied as a class by Hermann Staudinger.