Dr. Leo Marvin is a fictional character from the 1991 comedy film What About Bob?. Portrayed by Richard Dreyfuss, he is a successful psychiatrist who becomes increasingly frustrated with his patient, Bob Wiley, played by Bill Murray, who follows him on vacation. The film explores themes of mental health and the dynamics between therapist and patient, showcasing Dr. Marvin's struggle to maintain his professional demeanor while dealing with Bob's quirky behavior. Ultimately, the character's journey highlights the challenges and absurdities of the therapeutic relationship.