Promoting Secure 5G Act of 2021 This bill requires the Department of the Treasury to instruct the U.S. Executive Director at each international financial institution (e.g., the International Monetary Fund or the International Finance Corporation) that it is U.S. policy to support institutional assistance with advanced wireless technologies only if they provide appropriate security for users, encourage assistance with infrastructure or policy reforms that facilitate the use of secure advanced wireless technologies, and cooperate with institutional member states to strengthen international support for such technologies.