This article describes two studies based on an integration of theory and research in object relations and developmental social cognition. The following four dimensions were assessed in 2nd and 5th graders and in 9th and 12th graders using Thematic Apperception Test (TAT) responses and Ss' descriptions of meaningful interpersonal episodes: complexity of representations of people, affect-tone of relationship paradigms, capacity for emotional investment in relationships and moral standards, and understanding of social causality. In both studies, developmental differences emerged on all measures except affect-tone, as expected. Results document object-relational development beyond the preoedipal years and suggest the diagnostic importance of distinguishing multiple dimensions of object relations rather than considering object relations as a single or unitary developmental line.