The concept of psychosocial maturity is reviewed in preparation for the exploration of the feasibility of constructing a scale that measures maturity. Investigation produced a preliminary 54-item scale with high reliability and moderate validity, which is appended. A factor analysis of the scale supports the a priori structure by the theoretical model of maturity. The five factors comprising the maturity scale are: self-esteem, openness to change, independence, identity, and social tolerance. Data on random samples of approximately 3,000 fifth grade students and 3,000 11th grade students, and another sample of 1,500 blacks at each grade level, form the basis for various analyses. As predicted, girls, whites, and children from higher socioeconomic backgrounds obtain higher maturity scores than boys, blacks and children from lower social classes. Differences in psychosocial maturity due to sex increase from grade 5 to grade 11; differences due to race and social class narrow over these years. Psychosocial maturity accounts for about 16% of the variance in academic achievement (standardized test scores) at grade 5, but for only 6% of the variance in achievement at grade 11. The increasing independence of academic achievement from the culturally desirable attitudes and values contained in the maturity scale is a matter of potential interest to educators. (See also TM 000 774) (Author/PR)