Early childhood home visiting is a two-generation approach to promote positive health and well-being outcomes among people who are pregnant and families with infants and young children. A popular family support strategy for the past several decades, home visiting expanded exponentially in the United States when the federal Maternal, Infant, and Early Childhood Home Visiting Program (MIECHV) was authorized in 2010 through a provision within the Affordable Care Act. MIECHV currently funds evidence-based home visiting services in underserved and historically marginalized communities in all 50 states, 22 tribes, the District of Columbia, and five U.S. territories. It is widely accepted that achieving intended child and family outcomes through home visiting services requires “high-quality” program implementation, but the field lacks a standard definition or empirical evidence for what “quality” means in the context of home visiting. With the rapid expansion of home visiting that has accompanied MIECHV, there is increased interest from the field in having a shared understanding of home visiting implementation quality that is applicable across models and accounts for dimensions of quality across the entirety of the home visiting implementation system. This paper describes the process used to develop a conceptual framework to understand home visiting quality. We engaged MIECHV awardees and other experts from the fields of home visiting, early childhood, implementation science, and health equity in a co-design process that involved initial brainstorming, a series of iterative framework drafts, and finalization of the model. The resulting framework captures the multiple levels (i.e., the contexts, agencies, entities, and individuals) that are part of the home visiting system and the theorized key aspects of quality that are applicable across the levels of the systems. We discuss potential uses of the conceptual framework, as well as lessons learned from the co-design process. (author abstract)