Equal Pay for Servicewomen Act This bill requires the Department of Defense (DOD) to address out-of-pocket cost inequities for military service uniforms. Specifically, the bill requires DOD to implement the four recommendations made by the Government Accountability Office in its report titled Military Service Uniforms DOD Could Better Identify and Address Out-of-Pocket Cost Inequities (GAO-21-120). The recommendations made in the report are related to reducing differences in out-of-pocket costs incurred by enlisted service members across the services and by gender. The bill requires DOD to prescribe regulations to ensure that out-of-pocket uniform costs to officers or enlisted members may not exceed costs to other officers or members in their branch solely based on gender; and if a change to a uniform affects only officers or enlisted members of one gender, the officers or members must be entitled to an allowance equal to the out-of-pocket cost related to the change. DOD must provide a one-time allowance to female officers and enlisted members in an amount based on gender disparities in out-of-pocket uniform costs during the past 10 years and proportional to the length of service of the officer or member.