A quality improvement intervention for maternal and newborn health was carried out in southern Tanzania at the community level. It sought to improve health-seeking behaviors and uptake of community-level maternal and newborn health practices. A process evaluation populated using data primarily from in-depth interviews and focus group discussions with the intervention’s implementers was undertaken in four villages receiving the intervention to evaluate the intervention’s implementation, uncover facilitators and barriers of quality improvement, and highlight contextual factors that might have influenced implementation. Performance implementation scores were used to rank the villages. Identifying higher- and lower-performing villages highlighted key facilitators and barriers of community-level quality improvement related to support from local leaders, motivation through use of local quality improvement data, and regular education around quality improvement and maternal and newborn health. These findings can be taken formatively in the design of similar interventions in the future.