Andrew F. Lang is professor of history and constitutional studies in the School of Civic Leadership at the University of Texas at Austin. A historian of the nineteenth-century United States, he specializes in the American Civil War era and American intellectual thought. His scholarship has received the Society of Civil War Historians' Tom Watson Brown Book Award and ranked as a finalist for the Gilder Lehrman Lincoln Prize.

Lang’s current research focuses on Abraham Lincoln and the ancient virtue of gratitude. His work examines how Lincoln understood gratitude as essential to sustaining a free society, preserving constitutional institutions, and renewing the democratic order.

Lang serves on the executive council of the Society of Civil War Historians, is a vice president of the Abraham Lincoln Association, and sits on the advisory board of the John L. Nau III Center for Civil War History at the University of Virginia. His essays and reviews have appeared in American Historical Review, Wall Street Journal, National Review, The Dispatch, Coolidge Review, Journal of the Civil War Era, and in myriad scholarly collections and anthologies. From 2014 to 2026, he taught American history at Mississippi State University.