The purpose of this study was to investigate the construct validity of the Career Maturity Inventory with ninth grade pupils. To demonstrate the construct validity it must be shown that the Career Maturity Inventory correlates highly with other variables with which it should theoretically correlate, and that it does not correlate with variables from which it should differ. The model of career maturity is hierarchical and is organized according to four dimensions: Consistency of Career Choice, Realism of Career Choices, Career Choice Competencies, and Career Choice Attitudes. Since the Career Maturity Inventory was designed to measure the Career Choice Attitudes and the Career Choice Competencies dimensions in the model of career maturity, the expected relationships among career maturity, intelligence, and student achievement can be stated in hypothesis form and tested empirically. The sample consisted of all 312 ninth grade pupils enrolled in a rural public school in central North Carolina: 64 white males, 56 white females, 112 black males, and 80 black females. The tests used were the Career Maturity Inventory Attitude Scale and Competence Test, the Otis-Lennon Mental Ability Test, and the Reading and Language subtests of the 1970 Metropolitan Achievement Test. (Author/JEL)