The study aimed to investigate how gender dynamics influence interactions, communication, and leadership opportunities between male school principals and female teachers in Lagos State secondary schools in Nigeria. Despite women constituting the majority of teachers, their representation in school leadership remains limited. Feminist Institutional Theory developed by Mackay, Kenny and Chappell in 2010 was adopted as the theoretical framework for this study. This was considered suitable for this study because it explains how gendered hierarchies are embedded in school governance, leadership selection, and teacher-principal interactions, and also explains why women remain underrepresented in school leadership despite policies promoting equality. The study employed a qualitative approach with interpretivism as a research paradigm. Four public secondary schools from Oshodi and Mushin local governments in Lagos State were purposively chosen, and data were gathered through semi-structured interviews with four male head teachers and eight female teachers, along with non-participant observations of meetings, staffrooms, and daily school routines. This study used NVIVO version 14 to identify and code quotations, which were further analysed and synthesised to form higher themes, some of which emerged to address the research questions. Thematic analysis, following Braun and Clarke's six-phase framework, identified patterns across narratives and observations. Trustworthiness was ensured through member checking, peer debriefing, detailed descriptions, and strict adherence to ethical standards. Findings reveal deeply rooted gendered perceptions of roles. Male head teachers predominantly perceived their roles in masculine terms of authority, discipline, policy enforcement, and administrative oversight, viewing themselves as custodians of government directives. Female teachers described a wide range of responsibilities, including classroom instruction, emotional support, counselling, student welfare, and informal mentoring, reflecting a feminised division of labour that normalises nurturing roles for women while restricting their access to formal authority. Communication and decision-making were found to be hierarchical and male-dominated. Staff meetings and strategic discussions were generally led or dominated by men, whereas female teachers reported self censorship, fears of being perceived as disrespectful, and limited influence over key decisions. Despite formal merit-based promotion systems, women faced barriers such as opaque appointment processes, informal “godfather” networks, gendered expectations concerning availability and family roles, and leadership standards linked to toughness and strict discipline. Some male headteachers acted as allies by mentoring female teachers and advocating for more inclusive practices, demonstrating potential for change. The study concludes that gender dynamics are embedded within institutional structures and daily practices that perpetuate male dominance in leadership. It recommends gender-sensitive leadership policies, transparent promotion criteria, quotas or affirmative action for women in headship positions, gender-awareness training for senior staff, and structured mentorship and leadership programmes for female teachers. By focusing on head teacher/teacher relationships rather than solely student/teacher interactions, the research offers new empirical and theoretical insights into how gendered institutions shape professional relationships in Nigerian education and proposes concrete strategies to promote gender equity in school leadership.