Howard Gary Costigan (1904–1985) was an American radio commentator, political functionary, and politician. Costigan is best remembered as the Executive Secretary of the Washington Commonwealth Federation during the second half of the 1930 while he was simultaneously a secret member of the Communist Party USA (CPUSA); he later provided testimony in support of legislative committees investigating communist activities.

The Washington Commonwealth Federation (WCF) was a political pressure group established in the American state of Washington in 1934 as "Commonwealth Builders, Incorporated" (CBI). The organization changed its name to Washington Commonwealth Federation in 1935. The organization did not run political candidates in its own name but rather functioned as an organized faction in the Washington State Democratic Party.