Background: In Tanzania, maternal and newborn health outcomes have been slow to improve. The Expanded Quality Management Using Information Power (EQUIP) project was carried out in Tandahimba district from November 2011–April 2014. EQUIP engaged village volunteers in quality improvement processes in which they problem-solved around key issues related to maternal and newborn health in their communities. Examples of community-level quality improvement are rare and there is little documentation of these. Aim: To explore the implementation of community-level quality improvement in-depth, identifying its facilitators and barriers; to analyse community-level quality improvement within the context of community participation; to determine influencers of birth preparedness and health facility delivery; and to evaluate user perspectives around perceived quality of maternal and newborn health care. Methods: A mixed-methods process evaluation in four villages (November 2012– November 2013). A continuous household survey provided quantitative data around household behaviours and perceived quality of care. Results: Mentoring and coaching were required to strengthen volunteer capacities to do quality improvement. Support from village leaders, regular volunteer education, and use of local data were key facilitators of the intervention. Community participation was high with some indication of empowering processes. Volunteer-targeted practices like birth preparedness and health facility deliveries were carried out by a majority of women (95% and 68% respectively). Common reasons for these practices included education around their importance from multiple sources; feeling that making birth preparations would positively impact care received; and male involvement. Qualitative data highlighted instances of disrespectful or abusive care, suggesting improvements in quality of care are still needed. Conclusion: Village volunteers readily participated in EQUIP. With support, volunteers were able to use quality improvement to contribute positively to changing care-seeking and other behaviours around maternal and newborn health. However, improvements in care-seeking must be accompanied by improvements in quality of care.