Objectives. To improve COVID-19 vaccination rates in pregnant and recently pregnant women from a baseline rate of 30.8% to 60% over 6 months in a marginalized population. Methods. This quality improvement (QI) project was conducted in a federally qualified health center in Western New York between November 2021 and April 2022, using a Lean Six Sigma method. The QI team created a fishbone diagram, process flow map, and driver diagram. Significant barriers were multiple preferred languages, limited health literacy, and a knowledge gap. Increased vaccination rates were the outcome measure. The process measures were attendance at educational events and increased knowledge in community health workers (CHWs) and doulas. Education for CHWs and patients, creating multilingual educational resources, and motivational interviewing sessions for CHWs and patients were the major interventions. We performed data analysis by using weekly run charts and a statistical process control chart. Results. We achieved a sustainable increase in the COVID-19 vaccination rates in women from 30.0% to 48% within 6 months. Conclusions. Patient education in their preferred languages and at health literacy levels and CHWs' engagement played a crucial role in achieving success. (Am J Public Health. 2024;114(S4):S322-S329. https://doi.org/10.2105/AJPH.2024.307665).