Background/Context In light of the consistent underperformance of the comprehensive high school, districts across the country, mostly urban, have begun creating small schools, believing that they may offer a more personalized, supportive, and demanding learning environment. To explore this assumption, this article examines small-school reform through the lens of complexity theory, considering both the promise and problems associated with this approach to educational change. Purpose/Objective With complexity theory as an analytic lens, this article looks at extant research in the area of small-school reform. Specifically, the article draws on fundamental features of complexity theory (e.g., initial conditions, distributed authority, control parameters, fractals, and synergy) as a way to assess both the problems and promise of small-school reform. Intervention/Program/Practice This article focuses on the effects of small-school reform— specifically, the impact of small schools, defined in general as those that enroll between 300 and 450 students, have an explicit thematic focus, promote broad democratic participation for all community members, and attempt to personalize students’ education as a means to enhance educational achievement. Research Design Drawing on the lens of complexity theory, this article offers a secondary analysis of research that I and others have conducted. Employing specific features of complexity theory, this article offers an analysis of these studies from a new analytic perspective. Conclusions/Recommendations Overall, complexity theory is “good to think with.” It offers a systematic way to conceptualize and direct reform in a dynamic, nonlinear system. It is not precise, and certainly not predictive, but complexity theory—with its attention to changed interactions, initial conditions, distributed authority, control parameters, and fractals—offers a holistic framework for understanding the systemic nature of educational reform. Too often, efforts at educational change have been atheoretical, ignoring the multiple, interrelated, and interacting elements of our schools and school systems. Viewing the educational system as composed of isolated and discrete structures, such efforts assumed that complicated phenomena could be understood by analyzing their constituent parts, when in fact the sum of the whole was greater, and more complex, than the sum of the individual parts. Consequently, reforms modified one or two elements in a system apart from related elements, assuming that these actions would produce the intended outcome through a linear, cause-and-effect relationship. But often, the status quo endured. Rather than assuming such predictable and linear interactions among discrete elements in an educational system, complexity theory draws attention to the evolving interrelationships among system elements at various levels of the system. It offers a means to analyze emerging patterns and trends to illuminate how the disparate system parts are, or are not, working together.