103T00000X Psychologist

Definition

A psychologist is an individual who is licensed to practice psychology which is defined as the observation, description, evaluation, interpretation, and modification of human behavior by the application of psychological principles, methods, and procedures, for the purpose of preventing or eliminating symptomatic, maladaptive, or undesired behavior and of enhancing interpersonal relationships, work and life adjustment, personal effectiveness, behavioral health, and mental health. The practice of psychology includes, but is not limited to, psychological testing and the evaluation or assessment of personal characteristics, such as intelligence, personality, abilities, interests, aptitudes, and neuropsychological functioning; counseling, psychoanalysis, psychotherapy, hypnosis, biofeedback, and behavior analysis and therapy; diagnosis and treatment of mental and emotional disorder or disability, alcoholism and substance abuse, disorders of habit or conduct, as well as of the psychological aspects of physical illness, accident, injury, or disability; and psycheducational evaluation, therapy, remediation, and consultation. Psychological services may be rendered to individuals, families, groups and the public.

— NUCC Health Care Provider Taxonomy, version 26.1

Where 103T00000X sits

• Group: Behavioral Health & Social Service Providers — code 16 of 40 in the group
• Classification: Psychologist 103T00000X

This is the general code for Psychologist. 21 more specific codes sit beneath it; pick one of those when the provider's training or certification matches it, and this one otherwise. A provider may report more than one taxonomy code on an NPI but marks one as primary.

Medicare

CMS's taxonomy crosswalk links 103T00000X to Medicare specialty 62 (Psychologist, Clinical). That specialty — not the taxonomy code itself — is what Medicare enrollment records and uses for payment. 1,025 practitioners are enrolled under it nationally, and 23 other taxonomy codes map to the same specialty.

Other codes under the same Medicare specialty: 103TA0400X Addiction (Substance Use Disorder) Psychologist; 103TA0700X Adult Development & Aging Psychologist; 103TB0200X Cognitive & Behavioral Psychologist; 103TC0700X Clinical Psychologist; 103TC1900X Counseling Psychologist; 103TC2200X Clinical Child & Adolescent Psychologist; 103TE1000X Psychologist; 103TE1100X Exercise & Sports Psychologist; and 15 more.

Related codes

History of 103T00000X

NUCC's earliest recorded change to 103T00000X is from 2007 (modified definition).

• 2007-01-01 — modified definition

Using 103T00000X

The code goes in the taxonomy field of the NPI application in NPPES, and on claims where a payer asks for it — box 24J (shaded) or 33b on the CMS-1500 with the ZZ qualifier, or the PRV segment of an 837 electronic claim. Payers match it against the taxonomy on the NPI record and, for Medicare, against the specialty on the enrollment, so all three should agree. To see which code a provider uses, search their NPI in the lookup.

Sources: NUCC Health Care Provider Taxonomy code set, version 26.1 (CSV); CMS Medicare Provider and Supplier Taxonomy Crosswalk, August 2026; CMS Medicare Fee-For-Service Public Provider Enrollment, extract of 2026-09-29. Checked 2026-10-24. Methodology.