In 2008 he was awarded the Gold Medal Award For Life Achievement in the Application of Psychology by the American Psychiatric Association and the American Psychological Foundation named the "Theodore Millon Award in Personality Psychology" after him. Millon developed the Millon Clinical Multiaxial Inventory, worked on the diagnostic criteria for passive-aggressive personality disorder, worked on editions of the Diagnostic and Statistical Manual of Mental Disorders, and developed subtypes of a variety of personality disorders.
In 2008, he received a prestigious award from the American Psychiatric Association and the American Psychological Foundation. This award was named after Theodore Millon and recognized his contributions to psychology, including the creation of the Millon Clinical Multiaxial Inventory, work on diagnostic criteria for passive-aggressive personality disorder, editions of the Diagnostic and Statistical Manual of Mental Disorders, and development of subtypes of various personality disorders.