Women's political representation has become a critical indicator of democratic quality, institutional legitimacy, and international credibility. While existing scholarship has extensively examined the barriers limiting women's political participation in Nigeria, comparatively little attention has been devoted to understanding how women's representation influences the country's international standing and broader governance outcomes. This study examines the relationship between women's political representation and Nigeria's international standing by assessing the diplomatic and developmental implications of gender inclusion through the analytical lens of Feminist Institutionalism. Adopting a qualitative documentary research design, the study draws upon peer-reviewed literature, official government publications, reports of international organizations, and electoral data obtained from institutions including the Independent National Electoral Commission (INEC), the Inter-Parliamentary Union (IPU), UN Women, the United Nations Development Program (UNDP), the World Bank, and the African Union (AU). Data were analyzed using qualitative content analysis to identify institutional patterns linking women's political participation with democratic governance, diplomacy, and sustainable development. The findings demonstrate that despite Nigeria's extensive formal commitments to gender equality, deeply embedded informal political institutions, including patriarchal norms, patronage networks, gendered party structures, and unequal access to political resources, continue to constrain women's effective participation in political leadership. The study further reveals that women's political representation contributes significantly to democratic legitimacy, enhances Nigeria's diplomatic credibility and international standing, and supports sustainable development through improved policy responsiveness. The study concludes that strengthening women's political representation should be regarded not only as a democratic obligation but also as a strategic institutional investment capable of enhancing Nigeria's governance capacity, international legitimacy, and long-term development.