Reducing Duplication Overseas Act of 2012

Reducing Duplication Overseas Act of 2012 - Requires a federal agency that performs any foreign affairs functions and operates overseas to participate in the International Cooperative Administrative Support Services system for purposes of obtaining household furniture, furnishings, and appliance pools services, motor pool services, and management services unless such agency provides a detailed explanation that describes: (1) how such agency will provide the service outside the system, (2) the cost of the service, and (3) how providing the service outside the system will not increase overall costs. Requires such an agency to provide a detailed explanation certifying that the mission of the agency cannot be achieved by participation in the system.

Requires the International Cooperative Administrative Support Services Executive Board to allow an agency to act as an alternative provider for administrative services at an overseas post in place of the system if the agency: (1) demonstratives that it can provide the administrative service more efficiently, and (2) agrees to provide the administrative service to all other International Cooperative Administrative Support Services customer agencies at the overseas post.

Requires the Comptroller General (GAO) to submit a review of the system to specified congressional committees