Colonial Korean society was a crucible of ritual conflict and innovation. The confluence of Protestant expansion, Japanese colonization, and cultural nationalism during the early twentieth century brought sweeping changes to Korean ritual life, especially to the all-important Confucian rites of passage. This article examines print media discussions of Protestant rites from the late 1910s to the early 1930s to trace how religious difference emerged as a political problem for Korean cultural nationalists. Early on, Protestant missionaries had banned ancestral veneration and other folk customs while spreading liturgical (marriage and funerary) ceremonies, in an effort to inculcate orthodox doctrines among new believers. Converts’ rejection of indigenous Confucian rites in favor of their own practices, however, soon became the focal point of heated public debates. When Protestants condemned ancestral rites as idolatry, they maligned fellow Koreans as primitive. Meanwhile, the rapid proliferation of Western-style church weddings excessively disseminated religious practices. Above all, cultural nationalists grew alarmed at how faith communities threatened to splinter society, diverting Koreans away from national concerns toward sectarian interests. I argue that Protestant rites prompted nationalist intellectuals to grapple with the sacred and secular, ultimately producing a narrow vision of religion subsumed under the aegis of the nation.