Nonacosane is a straight-chain hydrocarbon with a molecular formula of C<sub>29</sub>H<sub>60</sub>, and the structural formula CH<sub>3</sub>(CH<sub>2</sub>)<sub>27</sub>CH<sub>3</sub>. It has 1,590,507,121 constitutional isomers.
Nonacosane occurs naturally and has been reported to be a component of a pheromone of Orgyia leucostigma, and evidence suggests it plays a role in the chemical communication of several insects, including the female Anopheles stephensi (a mosquito).
Nonacosane has been identified within several essential oils. It can also be prepared synthetically.