Dr. Peter X. Tierney, PHD

Dr. Peter X. Tierney is a Psychologist provider (Psychologist) practicing in Milton, MA, registered in the NPPES registry with NPI 1285780593 since 2007. The credential PHD stands for Doctor of Philosophy.

✓ Active NPI ✓ Valid NPI checksum Sole proprietor

NPI	1285780593
Entity type	Individual (Type 1)
Name	Dr. Peter X. Tierney
Credential	PHD
Sex	Male
Practice address	Milton, MA, 02186
Phone	6176982252
Enumeration date	2007-01-27
Last updated in NPPES	2007-07-08

Street address withheld — NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

Taxonomy code	Specialty	Primary	License	State
103T00000X	Psychologist	Primary	3636	MA

PHD — Doctor of Philosophy: A doctoral degree; in healthcare often held by clinical psychologists and researchers. About the PHD credential

Copy-ready billing details

Provider: Peter Tierney, PHD
NPI: 1285780593
Taxonomy: 103T00000X (Psychologist)
Address: Milton, MA, 02186

Other providers at this practice address

NPI	Name	Type	Specialty	Location
1780758243	Agnes Martin	Individual	School Psychologist	Milton, MA
1841338647	Kirsten Maclean	Individual	Psychologist	Milton, MA
1043350317	Anne Barrett	Individual	Adult Psychiatric/Mental Health Registered Nurse	Milton, MA
1902008626	Mary Carney	Individual	Psychiatric/Mental Health Clinical Nurse Specialist	Milton, MA

Verify this record

Cross-check NPI 1285780593 against the authoritative CMS record: view Dr. Peter X. Tierney on the official NPPES registry .

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes — even if the provider moves or changes specialty. Read the full guide or validate an NPI number.

Frequently asked questions

Is this the official NPI registry?

No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

What specialty is Peter Tierney?

Peter Tierney is registered in NPPES with the primary taxonomy of Psychologist. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

Source: CMS NPPES (public data). Snapshot 2026-07-11. Provider record last updated 2007-07-08.