Few spheres in life are as universally relevant for (almost) all individuals past puberty as sexuality. One important aspect of sexuality concerns individuals' sex drive-their dispositional sexual motivation. A vigorous scientific (and popular) debate revolves around the question of whether or not there is a gender difference in sex drive. Several theories predict a higher sex drive in men compared to women, with some theories attributing this difference to biased responding rather than true differences. Currently, there is little consensus on how to conceptualize sex drive, nor does a quantitative summary of the literature exist. In this article, we present a theory-driven conceptualization of sex drive as the density distribution of state sex drive, where state sex drive is defined as momentary sexual motivation that manifests in sexual cognition, affect, and behavior. We conduct a comprehensive meta-analysis of gender differences in sex drive based on 211 studies, 856 effect sizes, and 621,463 persons. The meta-analysis revealed a stronger sex drive in men compared to women, with a medium-to-large effect size, g = 0.69, 95% CI [0.58, 0.81]. Men more often think and fantasize about sex, more often experience sexual affect like desire, and more often engage in masturbation than women. Adjustment for biased responding reduced the gender difference (g = 0.54). Moderation analyses suggest that the effect is robust and largely invariant to contextual factors. There was no evidence of publication bias. The discussion focuses on validity considerations, limitations, and implications for psychological theory and people's everyday lives. (PsycInfo Database Record (c) 2022 APA, all rights reserved).