School culture represents the deeper values, beliefs, traditions, norms, and assumptions shared by a school community that shape "how we do things here." Culture is the school's personality—the underlying "why" behind behaviors, policies, and practices. It includes unwritten rules, shared stories, rituals and traditions, assumptions about learning and relationships, and collective identity.

Unlike school climate (which is more observable and changes relatively quickly), culture is ingrained and evolves slowly over years. Culture shapes everything: how adults interact with students, whether mistakes are learning opportunities or failures to hide, how conflicts get resolved, what gets celebrated and recognized, whether innovation is encouraged or risky, and fundamentally whether the community believes all students can succeed.

Research from Deal and Peterson emphasizes that school culture "is always at work, either helping or hindering learning." Positive cultures characterized by high expectations, mutual respect, collaboration, and growth mindset support student achievement and teacher satisfaction. Toxic cultures marked by low expectations, blaming, isolation, and resistance to change undermine even well-designed programs and talented staff.

For charter and private school leaders, culture affects retention powerfully but indirectly. Culture shapes climate (the atmosphere families experience daily), determines how schools respond to problems (defensively or constructively), and creates the conditions where students and staff either thrive or leave. Changing culture requires years of consistent leadership demonstrating values, but culture's impact on retention justifies the investment.