This study examined three different types of scheduling used in high schools: a traditional schedule, an A/B block schedule, and a 4 x 4 block schedule. The sample of 355 students was drawn from a city in northern Colorado where junior high schools that employed similar schedules served as feeders to the high schools. Findings from this study indicate that students participating in the school where 4 x 4 block scheduling is used may have an advantage in math and reading achievement over students in traditional and A/B schedules. Significant gains were discovered in reading achievement. Gains in math were smaller and not significant.