Completion of secondary school is increasingly viewed as a desirable life goal for young men and women in urban Kenya. Yet achieving this goal often conflicts with other key transitions to adulthood, such as becoming sexually active, marrying, having children, and finding employment. Drawing upon exceptionally rich life-history calendar data from young people in Kisumu, Kenya, we explore how the timing and sequencing of key transitions affects the likelihood of secondary school completion. Conversely, we also examine how school enrollment and performance affect the timing of sexual initiation. Our findings indicate that sexual activity and the transition toward family formation are largely incompatible with young women's schooling. For men, however, romantic and sexual partnerships have no impact on schooling unless a partner becomes pregnant. Instead, paid employment appears to be least compatible with continued education.