Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
Greg Klassen, PSY.D.
Psychologist in Lake Forest, CA · enumerated 2018.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1083100093
See something wrong? Report a correction
Registry record
Entity type Individual (Type 1)
Name Greg Klassen
Credential PSY.D.
Sex Male
Practice address 23792 Rockflield Boulevard, Suite 290, Lake Forest, CA, 92630
Phone (949) 303-8932
Enumeration date Jul 3, 2018
Last updated in NPPES Jul 3, 2018
Taxonomy & licenses
103T00000X Psychologist Behavioral Health & Social Service Providers · License PSY18605 (CA) Primary
PSYD · Doctor of Psychology: A clinical doctorate in psychology focused on professional practice.
About the PSYD credential
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.
Frequently asked questions
Where does Greg Klassen practice?
The practice location on file with NPPES is in Lake Forest, CA. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Greg Klassen?
The National Provider Identifier (NPI) for Greg Klassen is 1083100093, a Type 1 (individual) record in the CMS NPPES registry.
Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2018-07-03.