In the education system in Trinidad and Tobago, only 60% of students are achieving mastery in literacy and numeracy as documented by national tests. The purpose of this basic qualitative study was to explore principals' experiences leading strategic planning designed to increase achievement in literacy and numeracy in eight high-performing primary schools in Trinidad and Tobago. Fullan's change process theory provided the framework for the study. Data were collected from interviews with eight principals. Data analysis included coding, categorizing, and identifying themes. Findings indicated that principals plan, implement, and monitor the facilitation of change processes through in-depth strategies in teaching and learning with a continuous focus on literacy and numeracy. Findings also revealed that there is continuous professional development to support teachers and transform their capacity in practice. The extension and confirmation of knowledge were validated by the change process theory that change process at the campus level of the school must include strategies for improving the school. Findings may be used to evaluate strategic planning quality and assessment practices in low-performing schools in Trinidad and Tobago, and to improve principals' capacity for effective strategic planning.