Quick answers
- Where does Gregory J. Williams see patients?
- Medicare's clinician data lists 2 practice locations, including San Marcos, TX and Sherman, TX. Call before your visit to confirm the address.
- What is Gregory J. Williams's specialty?
- Medicare lists Psychiatry as the primary specialty.
- Does Gregory J. Williams accept Medicare assignment?
- Medicare's clinician data says Gregory J. Williams may accept Medicare assignment (as of 2026-10-02). Ask the office whether they accept it for your visit.
- Does Gregory J. Williams offer telehealth?
- Medicare's clinician data says Gregory J. Williams offers telehealth services. Ask the office which visits can be done by video or phone.
- What is the phone number for Gregory J. Williams?
- (844) 824-8775, as listed in official Medicare / NPI Registry data.
- What is Gregory J. Williams's NPI number?
- 1891910659. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Practice locations
Addresses where Gregory J. Williams is enrolled with Medicare (CMS data updated 2026-10-02).
- 151 Stagecoach Trl, Suite 220San Marcos, TX 78666 (844) 824‑8775
- 425 N Highland Ave, 260 Dfw Physicians Medical Associates LLCSherman, TX 75092 (903) 957‑0082
Group practices
Medicare enrollment lists Gregory J. Williams as a member of these groups (CMS data updated 2026-10-02).
- Progressive Behavioral Health, PLLC386 clinicians in the group
- DFW Physicians Medical Associates LLC15 clinicians in the group
Specialties
- Psychiatryprimary
Other psychiatrists in San Marcos
Clinicians with the same Medicare primary specialty in San Marcos, TX — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Uniformed Services Uhs Fe Hebert School Of Med |
| Graduation year | 2005 |
| Gender (as listed) | Male |
| Medicare assignment | May accept for some services |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1891910659 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians