Recent studies suggest that body height has an effect on the intensity of jealousy among men and women. Since short men and both short and tall women are regarded as less attractive, they could be at greater risk of being cheated by their partners and therefore more jealous. Numerous studies have documented sex differences in jealousy about a partner’s sexual and emotional infidelity with a person of the opposite sex. However, the partner’s ex as a rival has been neglected in the literature. Therefore, in this study the relationships between height and jealousy about two types of infidelity among 112 heterosexual men and 314 women were investigated. Infidelity scenarios included two types of rival: new rival and partner’s ex. As expected on the basis of prior studies, men were more jealous of sexual infidelity and women of emotional infidelity. Both sexes reported greater jealousy over a new rival than over partner’s ex. Among men, there were no relationships between height and jealousy, while among women, significant linear and curvilinear relationships were found for sexual infidelity with an ex-girlfriend. Jealousy was lowest among tall women and highest among short and medium-height women. The results were interpreted within the framework of evolutionary psychology.