Courtney A. O'Brien, DO
Accepting New Patients

Courtney A. O'Brien, DO

  • Rheumatology
Average rating: 5.0
 
Simi Valley Primary & Specialty Care |
2655 1st Street, Suite 380 Simi Valley, CA 93065
805-583-7640
+1 more location
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About

Dr. Courtney O’Brien is a board certified rheumatologist who practices in Simi Valley and Porter Ranch. She provides comprehensive care in general rheumatology with particular clinical interests in musculoskeletal ultrasound, osteoporosis, lupus, vasculitis, and inflammatory arthritis.

Dr. O’Brien earned her medical degree from Nova Southeastern University College of Osteopathic Medicine, where she received additional training in osteopathic manipulative medicine, emphasizing a holistic approach to patient care. Her passion for rheumatology was sparked early in her medical education through volunteer work with children affected by juvenile arthritis. She went on to complete her internal medicine residency at Rush University Medical Center in Chicago and her rheumatology fellowship at UCLA. She is certified in musculoskeletal ultrasound through the USSONAR program and integrates this advanced imaging technique into her clinical evaluations to ensure accurate and thorough diagnostic assessments.

Dr. O’Brien is also dedicated to global health and has participated in numerous medical outreach initiatives throughout Latin America and the Caribbean, delivering care to underserved populations. 

In her leisure time, Dr. O’Brien enjoys a variety of outdoor activities, including hiking, paddle boarding, skiing, roller skating, camping, and beach volleyball.

Languages

English

Education

Medical Board Certifications

Rheumatology, American Board of Internal Medicine, 2022
Internal Medicine, American Board of Internal Medicine, 2020

Fellowship

Rheumatology, University of California, Los Angeles, 2022

Residency

Internal Medicine, Rush University, 2020

Degree

DO, Nova Southeastern University College Of Osteopathic Medicine, 2017

Recognitions

  • Super Doctors® Southern California Rising Stars 2025

Locations

Hospital Affiliations

Ronald Reagan UCLA Medical Center

Medical Services

Rheumatology

Insurance

  • Aetna
  • Anthem Blue Cross
  • Blue Shield of California
  • Centivo
  • Cigna
  • First Health
  • Health Net of California
  • Interplan (part of HealthSmart)
  • Medicare Advantage
  • MultiPlan
  • UFCM Health System
  • Prime Health Services
  • Private Healthcare Systems (PHCS)
  • TRICARE
  • UnitedHealthcare

The list of health care plans above may not be comprehensive and could change. 
Please contact your benefits coordinator or health insurance company directly to verify coverage.

Visit our health insurance information page for more details.

Recognitions

  • Super Doctors® Southern California Rising Stars 2025

Reviews

Overall rating: 5.0
220 total ratings | 160 reviews
5.0
November 26, 2025
Dr. O?Brien was wonderful in answering all my questions and providing useful guidance. I wish all doctors were as knowledgeable, empathetic and truly caring for patients as Dr. O?Brien
5.0
November 25, 2025
She is very knowledgeable and smart. She listens to you and provides you with information that help you to understand your problems. I am very happy with my provider.
5.0
November 19, 2025
Dr. Courtney O?Brien is very proactive and always offers suggestions to assist her patients concerns and dude effects from meds. She is a team player and will happily email other doctors on my team with her observations and recommendations. She?s very friendly and approachable.
5.0
November 18, 2025
dr. O is very knowledge, kind, and provides top notch care.
5.0
November 14, 2025
Dr O?Brien is excellent and very knowledgeable
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