By focusing on the American Protective Association (A.P.A.), this article demonstrates how anti-Catholicism influenced free labor ideologies and working-class movements during the Gilded Age. The labor movement in the late nineteenth century generally believed that the so-called “dangerous classes” threatened working-class social mobility and economic independence. Religious bigotries, though, often dictated which people and institutions were considered economically dangerous. This article argues that, as anti-Catholic stereotypes collided with emergent anti-monopoly critiques, some working-class reformers saw Catholicism as incompatible with traditional notions of free labor. These reformers embraced anti-Catholic politics and chose to establish, join, or support the A.P.A. Many in the A.P.A. thought Catholic workers lacked the autonomy necessary to be free laborers, leading to intra-union conflict and a distrust of labor organizations with significant Catholic membership. They also charged that the Catholic Church itself opposed free labor and was already profiting off slave labor in institutions like the Houses of the Good Shepherd, a charitable institution, which sought to reform “abandoned women.” Ultimately, the A.P.A. and its anti-Catholic bigotries contributed to the fragmentation of the working class in Gilded Age America in ways that scholars have not yet recognized.