Southeast Asia is one of the most dynamic regions in the world. It is experiencing rapid socioeconomic change that may influence the level of sexual aggression, but data on the scale of sexual aggression in the region remain sparse. The aim of the present article was to systematically review the findings of studies available in English on the prevalence of self-reported sexual aggression and victimization among women and men above the age of 12 years in the 11 countries of Southeast Asia (Brunei, Cambodia, East Timor, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam). Based on four scientific databases, the search engine Google, Opengrey database, and reference checking, 49 studies were found on sexual victimization. Of those, 32 included only women. Self-reported perpetration was assessed by only three studies and included all-male samples. Prevalence rates varied widely across studies but showed that sexual victimization was widespread among different social groups, irrespective of sex and sexual orientation. Methodological heterogeneity, lack of representativeness of samples, imbalance of information available by country, missing information within studies, and cultural differences hampered the comparability between and within countries. There is a need for operationalizations that specifically address sexual aggression occurring after the age of consent, based on detailed behavioral descriptions of unwanted sexual experiences and allied to a qualitative approach with cultural sensitivity. Data on sexual aggression in conflict settings and in human trafficking are also limited. Recommendations for future research are presented in the discussion.