United States Foundation for International Conservation Act of 2023 This bill requires the Department of State to establish the U.S. Foundation for International Conservation as a tax-exempt organization to promote international conservation efforts, including by providing grants for eligible projects. The foundation shall fund projects that support effective area-based conservation measures and the long-term management of protected or conserved areas and their contiguous buffer zones. Such areas include terrestrial, coastal, and marine-protected or conserved parks, conservancies, and reserves. Projects must be cost-matched from sources other than the U.S. government. Project grants shall focus on countries that (1) have low-income, lower middle-income, or upper-middle-income economies; (2) have a high degree of biological diversity or important species or ecosystems; and (3) have demonstrated a commitment to conservation through their actions. The foundation may not provide support for any government, or any entity owned or controlled by a government, that has repeatedly provided support for acts of international terrorism or has engaged in a consistent pattern of gross human rights violations. Additionally, the foundation may not engage in any dealings prohibited under U.S. sanctions.