Psychologists in Ontario, CA
Browse 10 Psychologist providers listed in NPPES with a practice address in Ontario, California.
How Ontario compares with the U.S.
Ontario has 5.5 Psychologists per 100,000 residents, about 39% of the U.S. rate of 14.
That is 10 active Psychologists with a practice address in Ontario, for a population of 180,547.
The California rate is 19 per 100,000 residents.
What these numbers mean
Clinicians per 100,000 residents compares places of different sizes. We count active clinicians who list a practice address in the area in the federal NPI registry (NPPES) and divide by the number of people who live there, according to the U.S. Census Bureau. The U.S. rate is the same calculation for the whole country.
A higher number does not mean it is easier to get an appointment, that wait times are shorter, or that care is better. It also does not show how many clinicians are accepting new patients or which insurance plans they take. A lower number does not by itself mean there is a shortage.
City counts use the city name in each clinician's practice address. That postal city can cover a larger or smaller area than the city limits the Census Bureau uses for population, and many clinicians list only one address even if they work in several places.
Too few Psychologists in Ontario are listed in the CMS Medicare file to report Medicare assignment or telehealth shares.
These figures summarize public federal data. They do not measure quality of care, appointment availability, or whether a clinician accepts your insurance or new patients. Registry addresses can be out of date. Please confirm details directly with the office and your plan. This information is not medical advice.
Prepared by T-MedInfo from NPPES, CMS and U.S. Census Bureau data. Questions or corrections: support@true-medinfo.com · Methodology
Sources: Clinician counts and practice addresses: NPPES NPI Registry, Centers for Medicare & Medicaid Services (CMS), data as of August 2026. Population: U.S. Census Bureau, American Community Survey 2020-2024 5-Year Estimates, Table B01003 (Total Population).
Dr. Pardis Amirhoushmand , PhD
Psychologist
Cassidy Erbst
Psychologist
Dr. Gabriela Gomes Costardi , DO
Psychologist
Dr. Makisha Alyce Lawrence , PsyD
Psychologist
Dr. Lisa Marie Lliteras , PsyD
Psychologist
Dr. Jennifer Kay Luu , PsyD
Psychologist
Dr. Melissa Matuszak , PhD
Psychologist
Dr. Jacquelyn Nguyen , PsyD
Psychologist
Nhung Phan
Psychologist
Dr. Sherif R Toma , PsyD
Psychologist
Frequently Asked Questions about Psychologist in Ontario
Each practitioner profile shows the NUCC taxonomy code and any state license number the practitioner reported to NPPES, plus a link to the California licensing board lookup. NPPES entries are self-reported; current license status is published only by the state board.
This list shows NPI records that are active in NPPES. A deactivated NPI keeps its profile with the deactivation date and practice history; find it with the site search by name or NPI number.
Other Specialties in Ontario
Psychologists in Other California Cities
Cities with the most listed practitioners first.