Stephen Albion Day (born July 13, 1882) was a Republican politician who represented the state of Illinois in the United States House of Representatives. Serving as a member of Congress during the early 1940s, he held office as a representative for Illinois at-large, reflecting a statewide constituency rather than a single geographic district.

Day began his congressional service on January 3, 1941, and served two terms in the House. His tenure concluded on January 3, 1945, marking a four-year period in which he participated in national legislative affairs during a critical era in U.S. history. Identified in congressional records by the biographical guide ID D000160, Stephen Albion Day is recognized as a historical member of Congress and a former officeholder for Illinois.