America’s tremendous diversities of faith, region, and ethnicity complicate efforts to generalize relationships between religious groups and the labor movement. Americans’ historic and widely shared commitment to Christianity masks deep divisions: between white Christians and black Christians, between Catholics and Protestants, between northern Protestants and southern Protestants, and between “modernist” Protestants (who view the Bible in metaphorical terms as a source of ethical guidance and emphasize social justice) and “fundamentalist” Protestants (who view the Bible literally and eschew social activism in favor of individual evangelizing). Work, class, and the role of the labor movement add extra dimensions to these complexities, which are multiplied when considering non-Christian traditions such as Judaism or the other world religious communities that have grown in the United States since the immigration reforms of 1965. Nevertheless, scholars accept a general narrative that delineates key periods, themes, and players over the course of the twentieth century. From the turn of the 19th century until the 1930s, the relationship between religion and labor was shaped by the centrality of the American Federation of Labor (AFL) in the labor movement, the development of a “social gospel” among northern mainline Protestants, and the massive immigration from southern and eastern Europe that brought millions of Catholic and Jewish workers into the United States before it largely ended in the 1920s. These developments were sometimes in tension. The AFL favored craft unionism and placed a premium on organizing skilled male workers; it therefore left out many of the unskilled new arrivals (as well as African Americans and most women). Consequently, the shape of “religion and labor” formed primarily around the dynamic between the AFL and Protestant social reformers, without much regard to the large masses of unorganized Catholic, Jewish, and African American workers. These dynamics shifted in the Great Depression. The Congress of Industrial Organizations (CIO), begun as a committee within the AFL in 1934, sought the organization of entire industries—skilled and unskilled alike, and ethnic Catholics and Jews became unionized in large numbers. Even traditional racial barriers in the labor movement began crumbling in some industries. And, the labor movement expanded its geographical ambition, pushing aggressively into the South. In turn, the religious voices associated with the labor movement broadened and deepened. Labor’s new alliances with Catholics, Jews, African Americans, and southern evangelicals helped to push the ranks of organized workers to historic highs in the 1950s. This coalition has faced divisive, even disastrous headwinds since the 1960s. The strength of anticommunism, especially within religious groups, caused some religious workers to retreat from the reformist ambitions of the labor movement and sparked a conservative religious movement deeply opposed to labor and liberalism. Race became an ever-hotter flashpoint. Although religiously affiliated civil rights reformers often forged alliances with unions, the backlash and resistance to civil rights among portions of the white working class undermined the efficacy of labor unions as sources of social cohesion. Perhaps most profoundly, the economy as a whole transformed from an urban-industrial to a post-urban service model. Organized labor has floundered in the wake of these changes, and the concomitant resurgence of a traditionalist, individualistic, and therapeutic religious culture has offered the remains of the labor movement little to partner with.