This study used a longitudinal sample of 9,160 children participating in the Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K) to: (a) describe characteristics of children who present with elevated internalizing symptomatology, (b) investigate stability of elevated internalizing status across early and middle childhood, and (c) explore possible relationships between elevated symptomatology in kindergarten and later academic competence and self-concept. Children were dichotomously categorized at kindergarten (Time 1), three years later (Time 2) and five years later (Time 3) as having either elevated or typical levels of internalizing symptomatology based on their scores on the internalizing subscale of an adapted version of the Social Skills Rating Scale (SSRS). Elevated internalizing symptomatology was unrelated to gender. In middle childhood more lower SES children than expected fell within the elevated category and fewer higher SES children than expected fell within the elevated category. Elevated internalizing symptomatology, as measured by teacher ratings, was associated with weaker academic skills and less social/behavioral competence at all three points in time. Elevated internalizing symptomatology was also associated with heightened internalizing and externalizing symptomatology, as measured by children's self-report, in middle childhood. Elevated internalizing symptomatology was negatively associated with social self-concept, but not academic self-concept. Teacher-rated elevated internalizing symptomatology was very unstable from early to middle childhood, and only slightly more stable within the middle childhood years. Kindergarten internalizing symptoms were not predictive of later self-concept and competency. The impact of selected socio-cultural factors (i.e., gender, race/ethnicity, SES) on temporal relationships was not significant. Results are discussed with regard to future directions for research and implications for practice. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]