Wartime Contracting Commission Reauthorization Act of 2021 This bill reestablishes the Commission on Wartime Contracting. The commission was established in 2008 to study U.S. wartime contracting in Iraq and Afghanistan. The bill replaces the commission's general duties to direct it to study (1) contracting funded by overseas contingency operations funds, and (2) contracting for the logistical support of coalition forces operating under the authority of the 2001 or 2002 Authorization for the Use of Military Force or for the performance of security functions in countries where coalition forces operate under that authority.