The article explores the role of gender policy as a strategic driver of institutional transformation and operational effectiveness within the Armed Forces of Ukraine (AFU) in the context of full-scale war. It offers a comprehensive analysis of the evolution of gender integration in the Ukrainian defense sector, tracing the trajectory from the initial regulatory reforms following the 2014 Russian aggression to the accelerated and systemic changes catalyzed by the 2022 invasion. Gender policy is examined not as a peripheral initiative but as a core component of defense modernization, resilience-building, and democratic civil–military relations. Special emphasis is placed on the implementation of institutional mechanisms aimed at ensuring gender equality and operational parity, including the expansion of women’s access to combat and command roles, the development of gender-sensitive infrastructure (such as separate sanitation facilities, childcare spaces, and rest areas), the introduction of gender-responsive budgeting (GRB), and the establishment of formal mechanisms for preventing and responding to sexual harassment and gender-based violence. The article also presents a comparative analysis of gender integration models in the armed forces of Israel, Norway, Lithuania, the United States, and Canada, examining personnel policies, recruitment and retention strategies, NATO interoperability standards, and social protection frameworks. Through this lens, Ukraine’s approach is shown to not only align with international norms and commitments—such as UNSCR 1325 and NATO’s Gender Perspective—but also to contribute to the emergence of innovative practices that may inform global defense reform agendas. The study concludes that the meaningful participation of women in the military is not merely a matter of formal equality or human rights compliance, but a strategic asset that enhances the adaptability, legitimacy, and combat effectiveness of the security and defense sector.