BuyAmerican.gov Act of 2021 This bill directs the President and specified federal agencies to take steps to increase transparency and limit the use of waivers of Buy American laws. Generally, Buy American requires agencies to procure domestic goods. The bill requires (1) the Department of Commerce to report periodically to Congress and the President on the implementation of, and compliance with, Buy American laws; (2) Commerce and the Office of the U.S. Trade Representative to assess the impacts of all U.S. free trade agreements and the World Trade Organization Agreement on Government Procurement on the operation of such laws; and (3) the General Services Administration (GSA) to establish a free, publicly available BuyAmerican.gov website. Public interest waivers from Buy American laws shall be construed to ensure the maximum utilization of goods, products, and materials produced in the United States. The President shall develop a mechanism to collect information on requests to waive Buy American laws and other domestic content restrictions for purposes of providing early notice to possible waivers via the website. Executive agencies shall make information concerning the intention to issue a waiver or exception in connection with a federal procurement available to the GSA at least 20 days prior to waiving a Buy American law. The Government Accountability Office shall report to Congress within two years of this bill's enactment describing the bill's implementation.