Research Findings: Drawing from cultural approaches to human development (Rogoff, 2003; Weisner, 2002, 2005) and cognition (Quinn & Holland, 1987), this article presents a working model and theory of change for quality in family child care by defining quality as the alignment of children's opportunities for learning and development with locally relevant ideals or cultural models. Providers--as the people responsible for organizing children's day-to-day activity--are conceptualized as the agents of change, and daily routine activities are the primary targets for quality improvement efforts. Sustainability, or how much daily routines fit with the conditions and meaning for participants in a setting, is hypothesized to moderate the impact of experiences in family child care on children's long-term development. Each component of the model is presented with supporting evidence from published and pilot research. Practice or Policy: Quality ratings capturing alignment between what is valued and done can better incorporate diversity in stakeholders' ideas about what matters for children and can offer parents and providers more descriptive information about quality and how to maintain or improve it. (author abstract)