Diana Butler Bass (born 1959) is an American historian of Christianity and an advocate for progressive Christianity. She is the author of eleven books.

Bass earned a PhD in religious studies from Duke University in 1991 with an emphasis on American ecclesiastical history, studying under George Marsden. From 1995 to 2000, she wrote a weekly column on religion and culture for the New York Times syndicate that appeared in more than seventy newspapers nationwide. She has blogged for the Sojourners God's Politics blog, On Faith at The Washington Post, Beliefnet, and The Huffington Post. She authored a Substack newsletter, The Cottage.

Bass is associated with Sojourners and is a member of the Episcopal Church.

Diana Butler Bass was born Diana Hochstedt Butler in 1959, in Baltimore, Maryland. She grew up in Scottsdale, Arizona. Raised a United Methodist, she became an evangelical. She attended Westmont College, a Christian college in Santa Barbara, California, from which she received a Bachelor of Arts degree in 1981.

Bass received a Master of Arts in Theological Studies degree in ecclesiastical history from Gordon-Conwell Theological Seminary in 1986. Studying under the supervision of George Marsden, she received a Doctor of Philosophy degree in religious studies from Duke University in 1991. Her doctoral thesis was titled Standing Against the Whirlwind: The Evangelical Party in the 19th Century Protestant Episcopal Church.

Following her first marriage, she married Richard Bass on January 18, 1997.

Bass worked primarily as an academic for a decade before becoming an independent scholar. She began in 1991 as an assistant professor of religious studies at Westmont College, from which she was fired in 1995. She went on to serve as a history instructor at the University of California, Santa Barbara, from 1995 to 1996, as a visiting assistant professor of religious studies at Macalester College from 1996 to 1997, and as an associate professor of religious studies at Rhodes College from 1997 to 2000. In 2002, the Lilly Endowment awarded Bass a major grant to support her research on mainline Protestant churches at Virginia Theological Seminary.

Bass's books range from a study of nineteenth-century evangelicalism (Standing Against the Whirlwind: Evangelical Episcopalians in Nineteenth-Century America) to a contemporary ethnography of mainline Protestantism (Christianity for the Rest of Us: How the Neighborhood Church Is Transforming the Faith) to theological explorations of contemporary life (Grounded and Grateful) to a spiritual memoir (Strength for the Journey: A Pilgrimage of Faith in Community), the latter of which records her growing dissatisfaction with conservative evangelicalism.