Research on sexual and gender minority student achievement indicates that such students report lowered achievement relative to other students. Increased victimization and less school belonging, amongst other factors, have been identified as contributing to these inequalities. However, supportive schooling structures and caregiver support may support their achievement. A nationally representative survey of secondary school students was used to identify specific factors that support achievement for sexual minority (n = 485), gender minority (n = 298), and heterosexual cisgender (where one's sex assigned at birth "matches" a binary gender identity, i.e., a male assigned at birth identifies as a boy/man, n = 7064) students in New Zealand. While reported victimization did not affect achievement for sexual and gender minority students, school belonging, and teacher expectations of success, emerged as significant factors. Differences emerged between sexual minority and gender minority achievement factors, suggesting a range of detailed policy implications and recommendations.