The International Monetary Fund’s 2022 Strategy to Mainstream Gender calls for an intentional and systematic approach to integrating gender into macroeconomic policies to foster strong, sustainable, and inclusive growth. This Note argues that the IMF is filling a critical gap in its mandate by mainstreaming gender into its work. It makes the case that (i) closing gender gaps is macrocritical because they go hand-in-hand with higher economic growth, greater financial stability, and lower income inequality. Not doing so would lead to underdevelopment, underutilization, and misallocation of productive human resources; and (ii) applying a gender lens to macroeconomic, financial, and structural policy design can help to narrow gender gaps and result in improved economic outcomes. This Note provides an overview of gender gaps in opportunities, outcomes, and representation; takes stock of how these gaps impact macroeconomic and financial outcomes; and identifies polices to narrow these gaps. It explains how narrowing gender gaps can benefit societies and outlines steps countries can take to unleash the economic gains from gender equality.