Dr Martha Sweezy is a psychotherapist and Assistant Professor of Psychiatry, part-time, at Harvard Medical School, Harvard University. She is one of the world's foremost authorities on Internal Family Systems (IFS) therapy and has a private practice in Northampton, Massachusetts.

Dr Sweezy has been practicing psychotherapy for more than 30 years and is a leader in her field. She is a clinical, program, and research consultant for IFS at Cambridge Health Alliance, where she was formerly the Associate Director and Director of Training for Dialectical Behavior Therapy (DBT).

Dr Sweezy has authored, edited, and co-authored numerous articles and books on topics that include DBT and the IFS perspective on addiction, trauma, couple therapy, shame, guilt, anxiety, depression, and more. Her latest co-authored title, Internal Family Systems Couple Therapy Skills Manual: Healing Relationships with Intimacy from the Inside Out, is a must for couple therapists.