Purpose/Objective: This study was conducted to examine the associations between generic and condition-specific health self-management and levels of adaptive behavior in 2 groups of transition-age youth with congenital neurodevelopmental conditions. Method: The sample included 43 adolescents/young adults diagnosed with cerebral palsy (CP) and 36 with spina bifida/myelomeningocele (SBM), ages 13–29, mean age 18.96 (4.77), 51.9% female. Health self-management was assessed with the Transition Readiness Assessment Questionnaire (TRAQ) completed by the child, and the Kennedy Krieger Independence Scales–Spina Bifida (KKIS-SB) completed by the parent/guardian. The Adaptive Behavior Assessment System (ABAS-II) completed by the parent/guardian was used to assess levels of adaptive behavior. Results: There were significant group differences in condition-specific health self-management, including lower KKIS-SB Initiation of Routines and KKIS-SB Prospective Memory scores in the group with SBM. Those differences were no longer significant when scoring was modified to account for item applicability. Group differences in generic health self-management and adaptive behavior were not significant. There were significant differences in the correlations between health self-management instruments and ABAS-II composite scores. Conclusions: For youth with congenital neurodevelopmental conditions who are in the transition to adulthood, there are important condition-specific self-management needs that are not captured by measuring generic transition readiness or adaptive behavior. Findings highlight the need for clinicians to assess health self-management needs from multiple perspectives, utilizing generic and condition-specific measures that can inform targeted interventions and supports for optimal independence.