Non-consensual sex poses a threat not only to sexual health but also to mental and physical health in general. HIV pre-exposure prophylaxis (PrEP) users might be particularly vulnerable to non-consensual sex because of interplaying factors such as mental health disorders, a high number of sex partners, engagement in chemsex, and the widespread use of dating apps. The objectives of this study were to assess the occurrence of non-consensual sex, its associated factors, and related help-seeking behavior among PrEP users. We analyzed data from an online survey among PrEP users in Belgium (09/2020-02/2022). Almost one in five participants (34/187, 18.2%) reported having ever experienced non-consensual sex. The most reported form was having sex against one's will, followed by having been given drugs against one's will, and having had sex without a condom against one's will. The vast majority of those who had experienced non-consensual sex (29/34, 85.3%) did not seek help afterward, mostly due to a lack of perceived need (21/29, 72.4%). Reported barriers to seeking help were shame (6/29, 20.7%) and lack of awareness of help services (3/29, 10.3%). Having experienced non-consensual sex in the past five years was associated with younger age and suicidal ideation in a multivariable logistic regression model. We conclude that addressing barriers to non-consensual sex help services is crucial to maximize their use and minimize the consequences of non-consensual sex experiences. PrEP consultations also represent an opportunity to offer such help given PrEP users are already familiar with these PrEP services and engaged in care.