Robert Carman Coates (born March 10 1928) is a former Canadian politician and Cabinet minister.

Coates was first elected to the Canadian House of Commons in the 1957 Canadian election as the Progressive Conservative MP for Cumberland, Nova Scotia. Coates was a backbencher during the Diefenbaker and Clark governments before being appointed to the Cabinet of Brian Mulroney as Defence Minister following the Tory victory in the 1984 Canadian election. Coates main initiative was the reintroduction of separate uniforms for the naval, land and air branches of the military. Paul Hellyer had unified the Royal Canadian Navy, Canadian Army and Royal Canadian Air Force into an integrated Canadian Forces with a single uniform in 1967. Coates and other Conservaties had long derided this decision as disrespectful of tradition. While Coates reintroduced distinct uniforms for each service he was unable to reverse the unification of the forces.

Coates was forced to resign from Cabinet on February 12 1985, three months after taking office, for breaching security by visiting a strip bar in West Germany and chatted with strippers while he had secret NATO documents in his possession. The resignation was the first to hit the Mulroney government. Coates returned to the backbench and did not run in the 1988 Canadian election.