This study sought to determine the magnitude and direction of achievement gender differentials at the UWI medical school in St. Augustine. This tertiary institution provides a unique opportunity to investigate gender differentials in the English-speaking Caribbean because males and females are self-selected and equally matched in ability. The study is set in the context of a variety of innovative teaching-learning strategies, assessments modes, and disciplines throughout an extended 5-year programme. Data for 9 years (graduating class 1994 to 2002) were collated and analyzed. The size and direction of differentials were evaluated using Cohen's D and Eta-squared. Additionally, the Standard Deviation Ratio (SDR) was used to compare variability in score distributions.