Active NPI
Stephen R. Knowlton, PHD
- Clinical Psychologist
- Boston, MA
National Provider Identifier
1336291004
On this page
Key facts
NPPES NPI Registry- Primary specialty
- Clinical Psychologist
- License
- 6510
- Practice address
- 466 Commonwealth Ave
Suite 201B
Boston, MA 02215-2721 - Phone
- (617) 859-5806
- NPI assigned
- Jan 16, 2007
- Sex
- Male
- Sole proprietor
- Yes
NPPES NPI Registry
Registry information is reported by the provider to CMS and is not verified. About this source
Specialties & licenses 2
| Specialty (taxonomy) | Code | License | State | Primary |
|---|---|---|---|---|
| Psychologist | 103T00000X | 6510 | MA | |
| Clinical Psychologist | 103TC0700X | 6510 | MA | Primary |
Addresses
Primary practice location
466 Commonwealth Ave
Suite 201B
Boston, MA 02215-2721
Mailing address
466 Commonwealth Ave
Suite 201B
Boston, MA 02215-2721
Phone (617) 859-5806
Medicare participation
Medicare enrollment files- Medicare fee-for-service enrollment
- Not listed in the public Medicare enrollment file
- Opted out of Medicare
- Yes, effective Jan 1, 2025 through Jan 1, 2027
National Provider Directory
National Provider Directory- Medicare enrollment (NPD)
- Enrolled
- Credentials
- Doctor of Philosophy
State licenses
| License | State | Type | Specialty |
|---|---|---|---|
| 6510 | MA | MD | Mental Health Counselor |
NPI Registry JSON
The complete NPPES record for this NPI in the NPI Registry API format.
{
"created_epoch": "1168905600000",
"enumeration_type": "NPI-1",
"last_updated_epoch": "1757548800000",
"number": "1336291004",
"addresses": [
{
"country_code": "US",
"country_name": "United States",
"address_purpose": "MAILING",
"address_type": "DOM",
"address_1": "466 COMMONWEALTH AVE",
"address_2": "SUITE 201B",
"city": "BOSTON",
"state": "MA",
"postal_code": "022152721",
"telephone_number": "617-859-5806"
},
{
"country_code": "US",
"country_name": "United States",
"address_purpose": "LOCATION",
"address_type": "DOM",
"address_1": "466 COMMONWEALTH AVE",
"address_2": "SUITE 201B",
"city": "BOSTON",
"state": "MA",
"postal_code": "022152721",
"telephone_number": "617-859-5806"
}
],
"practiceLocations": [],
"basic": {
"last_name": "KNOWLTON",
"first_name": "STEPHEN",
"middle_name": "R.",
"credential": "PHD",
"sole_proprietor": "YES",
"sex": "M",
"enumeration_date": "2007-01-16",
"last_updated": "2025-09-11",
"status": "A"
},
"taxonomies": [
{
"code": "103T00000X",
"taxonomy_group": "",
"desc": "Psychologist",
"state": "MA",
"license": "6510",
"primary": false
},
{
"code": "103TC0700X",
"taxonomy_group": "",
"desc": "Psychologist, Clinical",
"state": "MA",
"license": "6510",
"primary": true
}
],
"identifiers": [],
"endpoints": [],
"other_names": []
}Other providers in Boston, MA
Sources for this page
- NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Sep 11, 2025; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
- Medicare enrollment (CMS PECOS): enrollments, PAC IDs and benefit reassignments; Opt Out Affidavits.
- National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.