Women are at higher risk than men for developing posttraumatic stress disorder (PTSD), but underlying mechanisms are still unclear. Comprehensive knowledge about these mechanisms is necessary to develop tailored, sex- and gender-sensitive preventive interventions. This systematic review and meta-analysis examined sex-/gender-dependent risk factors, that is, risk factors with sex/gender differences in (a) vulnerability or (b) prevalence/severity, as well as sex-/gender-specific risk factors, that is, and (c) risk factors present in one sex/gender only.