GAO has the authority to oversee bid protests involving many different government agencies. But its jurisdiction has limits, such as that it won’t consider protests of certain activities at the U.S. Mint.
One other limitation is that, when a federal agency provides funding to a non-federal entity and that non-federal entity procures services through competitive award, GAO will not consider a protest of that award. A recent GAO decision confirmed the lack of jurisdiction in a situation involving a competitive procurement by a federally recognized tribe using FEMA grant money.