Witt's research has generally focused on ancient philosophy, metaphysics and feminist theory. She has written extensively about the metaphysics of gender, about Aristotle (especially about Aristotelian metaphysics,) and feminist metaphysics. She has also written and spoken about the relationship between feminist philosophy and the traditional philosophical canon, arguing that feminist philosophy's enduring interest in the canon has been a process of historical self-justification (that is, justifying why feminist philosophy should exist,) and argues further that this is a process nearly identical to that that other emergent disciplines of philosophy undertook as they emerged. She has also published on the philosophy of adoption and the family.
