Family physicians are a key player in facilitating access to psychiatric treatment for people with first-episode psychosis, and this involvement can reduce aversive events in pathways to care. However, approximately a third of people do not seek help for mental health reasons from primary care in the period leading up to the first diagnosis, and it is unclear whether this help-seeking gap is related to lack of access to a regular family physician. Our objective was to estimate the proportion of people with first-episode psychosis who do not have access to a family physician at psychosis onset, and to examine and factors associated with lack of access. Using population-based health administrative data, we constructed a retrospective cohort of people aged 14 to 35 years with a first diagnosis of psychosis in Ontario between 2005 and 2015. We randomly selected four general population controls matched on age, sex, and neighborhood. We compared factors associated with access to a primary care physician at the time of psychosis onset between the two groups using prevalence ratios (PR) estimated from modified Poisson regression models with robust variance estimators. Over one quarter (28%) of young people with early psychosis (n = 39,449) did not have access to a family physician at illness onset. People with psychotic disorders were more likely to have a regular family physician relative to matched controls (PR = 1.28; 95%CI = 1.27, 1.29). However, after adjustment for physical and psychosocial comorbidities, people with psychotic disorders were less likely to have access to a regular family physician (PR = 0.96; 95%CI = 0.96, 0.97). Among young people with psychotic disorders, factors associated with lack of access to a family physician included older age, male gender, low neighborhood-level income quintile, residential instability, and migrant status. People living in rural areas and those with chronic physical or psychosocial comorbidities were more likely to have access to a regular family physician. Approximately one in four young people with early psychosis in Ontario lack access to a regular family physician at psychosis onset, suggesting that the help-seeking gap in primary care prior to the onset of psychotic disorder may be partially attributed to this lack of access. Interventions aimed at improving access to family physicians among vulnerable groups, and at supporting family physicians in referral to early psychosis intervention services, may improve pathways to care for youth with first-episode psychosis.