Triple oppression is a doctrine formulated by Black women in the Communist Party, USA beginning in the 1920s. It holds that Black working-class women in the United States are oppressed (or exploited) simultaneously in three different ways: first, along lines of gender inequality because they are women; second, racially because they are non-Whites; third, in the classic Marxian economic sense because they are wage workers. The terms triple exploitation and superexploitation have also been used to refer to this phenomenon.
The Black feminists in the CPUSA who formulated the theory in the '20s and '30s believed that because of their triply oppressed location in American society, working-class Black women were, potentially, one of the most revolutionary populations in the country.
A notable early proponent of the theory was Louise Thompson Patterson, who wrote of Black women's "triple exploitation" in her 1936 article "Toward a Brighter Dawn". CPUSA writer Claudia Jones popularized the concept in the post-WWII period as "triple oppression".
The following passage from Erik McDuffie's Sojourning for Freedom (2011) describes the theory:
Emphasizing the connections among racial, gender, and class oppression, the theory posited that the eradication of one form of oppression requires the concurrent dismantlement of all types of oppression. This conceptual framework, now referred to by feminist scholars as intersectionality, is most commonly associated with black feminism of the 1970s, arguably most powerfully articulated in the black socialist feminist manifesto of 1977, the Combahee River Collective Statement. However, I show how black Communist women were the first to explicitly articulate this theoretical paradigm. (P. 4.)