There have been appeals within the educational change (EC) and school improvement (SI) literature for research to explore more non-westernized and developing country contexts (Dimmock, 2000; Harris, 2009; Harris & Chrispeels, 2006; McMahon, 2006). This article is a response to those appeals. The study maps the SI educational policy contexts of Trinidad and Tobago (T&T), a developing country in the Caribbean from 1850 to 2010. Literature on EC and SI within this country and region is sparse. This article illuminates on research which reviewed the development of SI particularly in the secondary school sector. It identifies distinct phases of SI in T&T and proposes that these phases are linked to significant educational policy development eras within the country. A documentary-based research approach was employed. This investigation is significant because it documents the SI movement in T&T and provides an understanding of how the country experienced educational change.