Main findings are that competence is: (1) a multidimensional construct; (2) stable in terms of inter-individual differences in the Social and Cognitive domains across the four developmental periods; and (3) similar for both genders over time. Path analysis revealed that the stability of Social competence declined after middle childhood, suggesting inter-individual variability in terms of change. Cognitive competence, on the other hand, remained stable across all four time periods. Emotional competence was stable only between early and middle adolescence. The findings support the general principles of organizational theory. Research methodology involved identifying potential developmentally appropriate measures of competence: Social, Cognitive, and Emotional well-being. These three measures were then validated for each of the four developmental periods. Data on 191 children were drawn from the Minnesota Longitudinal Study of Parents and Children, a prospective study of low socioeconomic children presumed to be developmentally at-risk. Participants were recruited from public health clinics between 1975 and 1977. The analysis focused on discovering the structure and longitudinal trends of positive competence development in the children. Data analysis relied on the use of exploratory factor analyses and analyses of invariance. Future research should further examine the findings regarding no significant gender differences for indicators of competence, preferably using larger, more representative datasets. Tables, figure, references