The American Protective Association (APA) was an American anti-Catholic secret society established in 1887 by Protestants. The organization was the largest anti-Catholic movement in the United States during the later part of the 19th century, showing particular regional strength in the Midwest. The group grew rapidly during the early 1890s before collapsing just as abruptly in the aftermath of the election of 1896.
Unlike the more powerful Know Nothing movement of the 1850s, the APA did not establish its own independent political party, but rather sought to exert influence by boosting its supporters in campaigns and at political conventions, particularly those of the Republican Party.