Catherine Mowry LaCugna (d. May 3 1997) was a feminist Catholic theologian and author of God For Us. LaCugna's passion was to make the doctrine of the Trinity relevant to the everyday life of modern Christians.

Building on the work of Karl Rahner, LaCugna argued that the "demise of the doctrine of the Trinity" started when early church theologians had to respond to the teachings of Arius, arch-heretic of the Christian church. Arius' doctrine required a response, and the Church Fathers' response began the theological trek into speculation on the inner, hidden life of God, commonly referred to as the immanent Trinity. Whereas before, theologians had concentrated on the nature of God as revealed in His actions in history (commonly called the economic Trinity), now theology had to speculate on who God is when no one is looking.

According to LaCugna, the church father Augustine furthered this divide between economic and immanent Trinity with his psychological model of the Trinity, which described the inner life of God as being like a human's memory, intellect, and will. The real devil in these matters, though, was Thomas Aquinas, whose scholastic theology took theological speculation to a whole new level.

LaCugna's analysis of the development of the doctrine of the Trinity can be (and has been) challenged on many levels.

LaCugna earned her Bachelor's degree at Seattle University, her Masters and Doctorate at Fordham University, and joined the faculty at Notre Dame University in 1981. There, she taught systematic theology to graduate and undergraduate students, eventually holding the Nancy Reeves Dreux Chair of Theology at the University of Notre Dame.

Catherine LaCugna died at the age of 44, of cancer, and is buried in the Cedar Grove Cemetery on the Notre Dame campus.