School principals’ leadership styles play a major role in teachers’ performance. This paper examines the relationship between school principals' leadership styles, whether transformational or transactional, on teachers' achievement motivation. A total of 320 heads of instructional departments were randomly selected from randomly selected schools. The results revealed that a transformational leadership style was prevalent among principals, and teachers’ achievement motivation was positive. There was a positive correlation between the principals’ transformational leadership style and the teachers’ achievement motivation. Relevant recommendations are included.