Despite consistent evidence that sexual communication positively correlates with relationship and sexual satisfaction, there has been empirical murkiness regarding which aspects of sexual communication matter more or less for relationship and sexual satisfaction. A systematic meta-analysis was conducted to investigate if the strength of the association between sexual communication and relationship and sexual satisfaction varied by dimensions of sexual communication and individual, interpersonal, and cultural factors. The meta-analysis included 93 studies with 209 unique effect sizes, which represented 38,499 unique individuals in a current relationship. The multilevel meta-analysis evidenced a positive association between sexual communication and both relationship (r = .37) and sexual satisfaction (r = .43). For relationship satisfaction and sexual satisfaction, the effect size for quality of sexual communication (r = .43; .52) was larger compared to the frequency of sexual communication (r = .31; .31) and sexual self-disclosure (r = .28; .39). After controlling for the average age and relationship length of the sample, samples with married participants (r = .49) had larger effect sizes compared to samples with mixed relationship statuses (r = .35). Higher levels of individualism (b = .003) strengthened, and higher levels of gender inequality (b = −.06) weakened, the association between sexual communication and sexual satisfaction. Finally, when sociosexuality was low, sexual communication had a large association with relationship satisfaction for men (r = .69) and a small association for women (r = .16). Measurement, sample characteristics, and cultural factors have an important role in understanding the link between partners’ sexual communication and their relationship and sexual satisfaction.