California State University San Marcos has been rocked by four reported sexual assaults within two weeks of the autumn semester beginning, with four female students alleging they are victims of rape. The incidents have raised serious concerns about campus safety and prompted the university to increase security measures. University officials have stated they are taking the allegations seriously and that the police department is investigating.

The assaults were reported on 5, 6, 13 and 18 September at various locations including student residence halls and off-campus accommodation. Each victim reportedly knew their alleged attacker, and none of the incidents were witnessed by other students. No arrests have been made to date. In response, the university has increased security patrols and made escort services available to students, whilst maintaining year-round bystander intervention training and confidential advocacy resources. Social media discussion has raised concerns about dorm room subleasing to non-students, a practice some claim has persisted for decades.