Richard J. Foster is a Christian theologian and author in the Quaker tradition. He has been a professor at Friends University and has been the pastor of Evangelical Friends churches.

Foster is best known for this book Celebration of Discipline (ISBN 0060628391), which examines the place of disciplines (spiritual exercises) in the Christian life. It has sold over one million copies. He also wrote Streams of Living Water (ISBN 0060628227), which examines the place of the different spiritual traditions in Christianity, and edited Devotional Classics (ISBN 0060669667), a devotional guide featuring Christian wisdom through the ages.

Foster is also the founder of Renovare, a Christian renewal para-Church organization.

As Foster encourages the utilization of classical Christian wisdom, he functions within the realm of paleo-orthodoxy.