This study was designed to investigate the factorial pattern of the Intrinsic versus Extrinsic Orientation Scale (Harter, 1981), and the developmental trends of motivational and cognitive orientations in advantaged and disadvantaged schools. Subjects were 4287 third-to ninth-grade pupils in advantaged (N = 3005) and disadvantaged (N = 1282) schools. Confirmatory factor analyses revealed the same factorial pattern found by Harter as well as the existence of two high-order factors: Motivational Orientation (MTO) and Cognitive-Informational Orientation (CIO). Analyses of variance of Grade × Type of School revealed that (a) disadvantaged pupils were significantly higher than advantaged pupils on MTO; (b) the MTO scores of the disadvantaged group decreased from third to sixth grade, but drastically increased from sixth to seventh, eighth, and ninth grades, whereas the MTO scores of the advantaged group continued to decrease toward the ninth grade; (c) the CIO scores of the advantaged group were high in the third grade and stayed at about the same level across all grades, whereas the CIO scores of the disadvantaged group were lowest in the third grade, higher in grades 4-7, and highest in grade 8. Results were explained by referring to differential quality of school life of advantaged and disadvantaged schools. Further research is suggested in which family contexts and personality-developmental variables as well as situational factors such as across-school transition should be investigated. Educational intervention studies are suggested to assess their effectiveness on development of MTO and CIO.