Student sex-based harassment has a negative impact on individual students and on the school environment. This review of the literature describes the evolution of sex-based harassment from elementary through high school, clarifies the relationship between bullying and sex-based harassment, and summarizes the research-based system and individual factors that support the development of such harassment in schools. Based on the research, we recommend the adoption of a comprehensive planning process for prevention that addresses the factors that reinforce student sex-based harassment and supports the school's bullying prevention efforts. School counselors can advocate for and play a leadership role in both developing and implementing a school-wide plan that includes needs assessment and evaluation. We offer suggestions for system-wide and individual interventions for school personnel and Tier 1-3 prevention and problem-solving interventions for students to support a healthy school environment free of sex-based harassment.