INTRODUCTION: This study's objective was to compare COVID-19 vaccination rates between pregnant individuals in San Francisco and the city's similarly aged population and to identify the factors associated with vaccine uptake in the pregnant population. METHODS: This was a retrospective cohort study of all patients delivering at 2 hospitals in San Francisco from March 15, 2021, to October 15, 2021. Reference COVID-19 vaccination rates for San Francisco were obtained from the California Immunization Registry. The primary outcome was completion of a COVID-19 vaccine series among pregnant individuals compared with that in the San Francisco general population aged 18-45 years. Secondary outcomes included factors associated with COVID-19 vaccination among pregnant people. RESULTS: Of 2,294 pregnant individuals, 1,181 (51.5%) completed a COVID-19 vaccine series by delivery. Pregnant individuals were less likely to be vaccinated than the San Francisco population throughout the study period. Factors associated with lower vaccination rates in pregnant individuals included public insurance (AOR=0.21, 95% CI=0.16, 0.27), younger age (AOR=0.74, 95% CI=0.64, 0.86), English language preference (AOR=0.58, 95% CI=0.42, 0.80), and self-identified Black (AOR=0.26, 95% CI=0.17, 0.40) (ref: White), Hispanic (AOR=0.61, 95% CI=0.46, 0.81), or other (AOR=0.50, 95% CI=0.36, 0.68) race or ethnicity. CONCLUSIONS: COVID-19 vaccination coverage among pregnant people in San Francisco lagged behind that of the city's similarly aged population, particularly among those with public insurance and of non-White race. Despite locally high vaccine acceptance, additional efforts are needed to address barriers and reduce disparities in COVID-19 vaccination within the pregnant population.