Buy American Enhancement Act of 2011 - Defines "substantially all" for purposes of Buy American requirements to mean that articles, materials, or supplies shall be treated as made substantially all from articles, materials, or supplies mined, produced, or manufactured in the United States if the cost of the domestic components of such items exceeds 75% of the total cost of all such items.
Requires the head of each federal agency to ensure that certain contracts awarded by such agency include a provision requiring compliance with Buy American requirements.
Defines "waiver" for purposes of Buy American requirements. Requires the head of each federal agency to publish on the agency website a list of each waiver of such requirements within 30 days after it is granted.