Numerous studies consider competition and jealousy within an evolutionary framework, yet less is known about the relation between aggression vis-à-vis hypercompetitiveness (i.e., competing to win) and jealousy. We investigated the longitudinal relations between hypercompetitiveness, jealousy, and aggression and the moderating role of gender in a sample of 615 Canadian adolescents assessed annually from Grade 7 through Grade 12 using self-reports. A developmental cascade model accounting for within-time correlations, across-time stability, and cross-lag paths was used to analyze the data. Results indicated hypercompetitiveness was positively associated with aggression across several time points (Grades 7[right arrow]8, Grades 8[right arrow]9, and Grades 9[right arrow]10) and was associated with increased jealousy in Grades 11 and 12. Indirect aggression in Grade 12 was positively associated with higher levels of jealousy in Grade 11. Few gender differences were noted. The study provides evidence for a developmental model in which hypercompetitive and jealous youth become more aggressive over time.