The significance of ego development and object relations for adaptation and adjustment in middle childhood was examined in a study of 92 nine- to twelve-year-old children. Subjects completed the Sentence Completion Test (SCT) and the Blatt Object Relations Scale (BORS) in individual sessions. BORS ratings were factor analyzed and a predominant factor of parental nurturance emerged. This factor was positively related to children's self-reported perceptions of parental involvement and autonomy support but was unrelated to the SCT. SCT findings revealed an expected pattern for middle childhood with the preponderance of children falling into impulsive, self-protective, and conformist stages of ego development. Both the SCT and BORS were examined in relation to aspects of children's cognitive and social functioning, assessed via teacher ratings, peer sociometrics, self-evaluations, and academic achievement records. Results showed that the SCT was primarily related to cognitive complexity variables, while the object relations measure was associated with both peer and self-evaluations. These nonoverlapping relations with varied child outcomes are discussed both in terms of methodological limitations and theoretical significance.