Grant Albert Wacker (born 1945) is an American historian of Christianity in the United States.

Grant Wacker is the Gilbert T. Rowe Distinguished Professor Emeritus of Christian History at Duke Divinity School.

He taught in the Department of Religious Studies at the University of North Carolina at Chapel Hill from 1977 to 1992.

[1][2] A specialist in American Christian history, Wacker is the author or co-editor of nine books, including Heaven Below: Early Pentecostals and American Culture (Harvard University Press, 2001),[3] America's Pastor: Billy Graham and the Shaping of a Nation (Harvard University Press, 2014),[4] One Soul at a Time: The Story of Billy Graham (Eerdmans, 2019),[5] and more than two-hundred published articles, essays, and book reviews.

He is past president of the Society for Pentecostal Studies, past president of the American Society of Church History,[6] a former senior editor of Church History: Studies in Christianity and Culture, and a senior trustee of Fuller Theological Seminary.