Objective: Attachment theory provides a powerful framework for understanding individual differences affecting interpersonal relationships and a range of health behavior outcomes. However, no meta-analyses have yet to examine the relationship between adult attachment styles and risky sexual behaviors. The purpose of this meta-analysis was to synthesize the results of the association between adult attachment and risky sexual behaviors. Method: Keywords were searched via PsycINFO, Web of Science, and Google Scholar. We used comprehensive meta-analysis (CMA) 3.0 to systematically synthesize and analyze the 42 effect sizes from 16 studies (total N = 7,233). Results: Attachment anxiety has a small effect on having multiple partners (Fisher’s Z = .09, 95% CI [0.021, 0.154]; I2 = 80.4%) and engaging in condomless sex (Fisher’s Z = .09, 95% CI [.006, 0.175]; I2 = 82.5%), whereas attachment avoidance has a small effect on having multiple partners (Fisher’s Z = .06, 95% CI [0.019, 0.109]; I2 = 57.6%) but no effect on engaging in condomless sex (Fisher’s Z = .05, 95% CI [−0.024, 0.117]; I2 = 73.9%). Furthermore, average age of participants in a study (z = 3.31, β = .01, p = .001) and type of risk population (z = 3.03, β = .12, p = .002) were found to be significant moderators. Conclusions: Insecure attachment styles are related to risky sexual behaviors and the correlation between attachment anxiety and having multiple partners is stronger as the average age of participant increases and when the study population is specifically an at-risk population.