We present a developmental cascade model of the longitudinal relationships between internalizing symptoms, externalizing problems, and academic performance in middle childhood, utilizing a large sample (N = 1,771) from the United Kingdom in a 3-year, cross-lag design. Three hypotheses were tested: adjustment erosion, academic incompetence, and (cumulative) shared risk. In addition, we sought to examine whether developmental cascade pathways varied across gender, while also statistically exploring indirect, mediation pathways. Structural equation models that accounted for within-time covariance, data nesting, and temporal stability provided evidence of gender-specific effects as follows: externalizing-attainment adjustment erosion pathways were found only in boys, while attainment-internalizing/externalizing academic incompetence pathways were found only in girls. Analysis of mediation pathways provided further support for these gender-specific longitudinal profiles. Protective longitudinal internalizing-externalizing and externalizing-internalizing pathways were found for both boys and girls. Finally, while it improved model fit for both genders, the influence of cumulative shared risk on the aforementioned pathways was relatively meager, substantively affecting only one (externalizing-attainment adjustment erosion pathway in boys). The implications of these findings are discussed, and study limitations noted.