Sexual harm within nightlife settings is a public health concern. This study aims to investigate the nature and prevalence of sexual harm experienced by Australian nightlife patrons and examine sociodemographic and environmental factors associated with sexual harm. Street interviews were conducted with patrons (N = 232, 51.3% women) in one night-time entertainment precinct in Victoria, Australia. Logistic regression analyses examined individual (e.g., pre-drinking) and venue-level (e.g., lighting) predictors of sexual harm on the night of interview. In the past three months, over half (56.6%) of women and nearly one third (31.7%) of men reported experiencing nightlife-related sexual harm. Sexual harm most frequently occurred on the dancefloor, with the most common types of harm experienced on the night of the interview and in the past three months being unsolicited sexual comments, leering, and groping. Regression analyses indicated that participants who had experienced nightlife-related sexual harm in the past three months were more likely to experience sexual harm on the night of the interview (OR 6.12), while those who visited venues with brighter lighting (self-rated) were less likely to experience sexual harm (OR 0.73). The findings suggest that sexual harm is highly prevalent in Australian nightlife settings. To reduce nightlife-related sexual harm, future interventions should consider venue lighting levels and incorporate a more substantial security presence in high-risk areas.