This paper analyzes drivers and impediments to secondary school reform in Trinidad and Tobago during the period from 1999 to 2009. International assessment data suggested limited progress on improving system quality and equity. Several policy levers and barriers have been defined in current system reform theory. However, explanations for the failure or success of education reforms in Commonwealth small states must also consider theory related to their unique contexts, namely smallness and colonial history. In this study, whole system reform theory is bridged with contextualized small state and postcolonial theories to analyze themes derived from a qualitative analysis of experiences in a major reform project for the secondary school sector. The identified barriers to change were ambiguity, coherence, and stringency and the contextualized drivers were leadership, support, and participation. Small state and postcolonial theory had added explanatory value, providing more precise insights into the specific impediments to change within these contexts. (Contains 4 tables and 1 figure.)