Childhood sexual abuse (CSA) is a significant public health issue with profound and long-lasting effects on survivors' emotional, psychological, and sexual well-being. While extensive research has examined the interpersonal sexual challenges associated with CSA, less is known about its association with solitary sexual behaviors such as masturbation, particularly the underlying motives or reasons. This study examined the mediating role of post-traumatic stress disorder (PTSD) symptoms in the relationship between CSA and three specific masturbation motives: mood improvement, relaxation/stress relief, and sexual arousal decrease. A sample of 624 adults ( = 29.51 years,  = 10.23) completed an online survey assessing CSA history, PTSD symptoms, masturbation frequency, and motives for masturbation. Structural equation modeling (SEM) revealed that PTSD fully mediated the associations between CSA and the three masturbation motives. Specifically, CSA was associated with higher PTSD symptoms, which, in turn, were linked to higher levels of masturbation motives related to mood improvement, relaxation, and sexual arousal decrease. Notably, the direct associations between CSA and masturbation motives were not statistically significant. These findings suggest that masturbation may serve as a coping mechanism-either as adaptive emotional regulation or, at times, as a maladaptive response involving avoidance or distress.