Columbia is the monthly magazine of the Knights of Columbus, the world's largest Catholic family fraternal service organization. The magazine's editorial content is geared toward a general Catholic audience, though readership consists mainly of the nearly 2 million members of the Knights of Columbus and their families in the United States, Canada, the Philippines, Mexico, Poland, the Dominican Republic, Puerto Rico, Panama, the Bahamas, the Virgin Islands, Cuba, Guatemala, Guam, Saipan, Lithuania, Ukraine, and South Korea.

Columbia publishes separate French-language and Spanish-language editions containing content translated from the English edition, as well as an abridged digital-only Polish edition.