Complexity theories have in common perspectives that challenge linear methodologies and views of causality. In educational research, relatively little has been written explicitly exploring their implications for educational research methodology in general and case study in particular. In this paper, I offer a rationale for case study as a research approach that embodies complexity, and I explore the implications of a "complexity thinking" stance for the conduct of case study research that distinguishes it from other approaches. A complexity theoretical framework rooted in the key concepts of emergence and complexity reduction, blended using a both/and logic, is used to develop the argument that case study enables the researcher to balance the open-ended, non-linear sensitivities of complexity thinking with the reduction in complexity, inherent in making methodological choices. The potential of this approach is illustrated using examples drawn from a complexity theoretical research study into curriculum change.