Michael (Mike) Eigen (born January 11, 1936) is an American psychologist and psychoanalyst. He is the author of 27 books and numerous papers. He has given a private seminar on Donald Winnicott, Wilfred Bion, Jacques Lacan and his own work since the 1970s. Eigen is known for his work with patients "who had been given up on by others", including people who experience psychosis.

Eigen was born in Passaic, New Jersey, to a Jewish family, the son of Jeanette (née Brody), a teacher, and Sol, a lawyer. Eigen received his B.A. (with honors) in 1957 from the University of Pennsylvania and his PhD in 1974 from The New School. He married Betty Gitelman on December 27, 1980. Betty is also a therapist. Eigen stated that he admires her and says that she “can help and treat people no one else can help.” They have two sons, David and Jacob.

Eigen relates to his patients with humility and curiosity. He learns from his patients. In talking about his approach to therapy, he stated that "I am hoping, praying that something real, useful, something that touches another soul happens, something that helps others feel how much there is to feel, how precious psychic reality is, how precious and complex and amazing we are."

Eigen integrates mysticism and spirituality into his work with psychoanalysis. He draws on the work of a number of analysts and spiritual traditions in this work. He explained that he is "not a scholar, systematic reader, or follower of any school." Eigen is particularly engaged with the work of Wilfred Bion. Eigen described how "Bion uses many images and expressions from religious and mystical life to portray psychoanalytic processes."