International affairs is undergoing fundamental and rapid gendered change, spurred on by shifting social and governance norms and the adoption of explicit feminist foreign policies in some states. In instances, this has resulted in women’s increasing representation at the frontlines of global governance. Yet, progress is marred by women’s continued entrenched underrepresentation in leadership and experiences of challenges that have in cases increased, not decreased, in recent years. Against a background of COVID-19 and cascading crises, a rise in right-wing misogyny and anti-rights backlash, and archaically slow-moving institutions, women remain frequently sidelined, marginalised, undervalued, and overlooked in international affairs. Despite progress, international affairs has a gender problem, and remains one of the worst-performing sectors of the state. After studying women’s leadership and gender relations across four international affairs agencies spanning diplomacy, defence, national security, policing, and intelligence, this book contributes empirical data from the last 30+ years on women’s representation in a leading case context—Australia—to understand the disconnect between pockets of progress and undercurrents of resistance. Australia is a global leader in terms of representation of women and policy supports for gender equality in governance. Yet Australia also demonstrates how deeply gendered, racialized, and heteronormative international institutions remain. Through in-depth interviews with almost 80 global leaders, including with Australia’s first female prime minister, Julia Gillard, and first female foreign minister, Julie Bishop, this book delivers a much-needed intersectional feminist institutionalist approach to trace the evolution of inequalities in international affairs and interrogate why women still remain underrepresented in international affairs.