A large, controversial literature has examined the hypothesis that the attractiveness of potential partners predicts romantic desire more strongly for men than for women. Nevertheless, prior studies demonstrating this sex difference in photograph-evaluation contexts have used extremely small samples of stimuli, which is as detrimental to statistical power as the use of small samples of participants. The current registered report used very large samples of both participants (N = 1,204) and stimuli photographs (N = 593) to test the sex difference in the attractiveness-desire association. The sex difference emerged with objective assessments of attractiveness from independent raters (approximately q = .13, a small effect) but not with participants’ own assessments of attractiveness (q = .00). Various other moderators that have been summoned to explain cross-study variability in prior research received no support (e.g. the sex difference was not larger in serious relationship contexts, the low-to-moderate range of attractiveness, etc.). Surprisingly, in the small sample of participants who were attracted to same-sex individuals, the attractiveness-desire association was stronger for women than men – the opposite of the sex difference anticipated by prior mate preferences research. This study provides effect-size benchmarks for studies of sex differences and highlights the importance of stimulus sampling when documenting replicable effects.