This ethnographic study aims to understand school-based gender interaction and its implication on the practices of Sexuality Education (SE) in a public primary school in Ethiopia. The study engaged Connell's gender theory to explain the gender interaction from gender division of labor, power relation and cathexis dimensions. The study employed school observations, Focus Group Discussions (FGDs) with students (age 13-16), and in-depth interviews with sexuality education teachers. The findings showed that the selected school is a gendered site in the aspects of division of labor, power relation and cathexis, where boys and girls learn and perform gender through various processes inside the classroom, outside the classroom, and in the immediate school surroundings. The findings also indicated that sexuality education responded to this by taking dual and complex role by both emancipatory (by challenging overall social gender power patterns) and reproducing gender relations (by neglecting the school-based gender bias). The study suggested the need to continuously reflect and reimagine the gender values embedded in sexuality education to improve gender relations in school context.