Objective This study aims to describe the frequency and timing of physician referrals to physical therapists (PTs) and other treatments prescribed over 12 months in patients with recent onset of knee osteoarthritis (KOA). The study also aims to identify determinants of early PT referrals. Methods A retrospective study was conducted using electronic medical records from an integrated health care system in the United States. Incident KOA visits between October 2016 and September 2017 were identified using International Classification of Diseases, Tenth Revision codes. Early PT referral was defined as a referral within 15 days of the incident KOA visit by the attending physician. Data on PT referrals, other KOA treatments, patient characteristics, physician specialty, practice location, and volume of patients with KOA were extracted. The number of licensed PTs within the county of the included practices was also obtained. We used generalized linear mixed models to predict factors associated with early PT referrals. Results Included in our study were 9,835 patients with incident KOA. Within the 12‐month period, 26% of patients had at least one PT referral (n = 2,550) and the median (interquartile range) days to the first referral was 0 (0–34) days. Early PT referral by the index physician occurred in 16.5% (n = 1,629) of patients, was less likely for patients with higher or missing knee pain scores and in rural practices, and more likely in women, patients with higher body mass index, and those seen in counties with a greater supply of licensed PTs. Conclusion Physician referrals to PT for a new episode of KOA are infrequent and influenced by patient and practice factors.