The call for accountability within education has led to the increased examination of the academic achievement of students across the nation. Too often, however, schools and school districts are scrutinized by means of overly simplistic linear models that fail to consider the complexity of interactions that result in student achievement. This paper postulates that student achievement is instead best understood as a developmental outcome that emerges as a result of interactions among layers within a complex system. Organizations such as schools can be modeled using Bronfenbrenner’s ecological systems and analyzed using complexity theory as an appropriate and useful alternative to the linear models that often form the basis of educational research and policy. Key elements of both Bronfenbrenner’s ecological-contextual theory and complexity are explained and applied at the level of an individual school.