The authors construct a model of psychosocial maturity which specifies measurable attitudes and dispositions in personal and social growth for secondary school students. Through integrating sociological and psychological views, the model outlines the following general dimensions of maturity relevant in all societies: (a) the capacity to function adequately on one's own; (b) the capacity to interact adequately with others; and (c) the capacity to contribute to social cohesion. The authors then define nine attributes judged pertinent to these capacities in this society. The final sections of the paper discuss problems in the measurement of psychosocial maturity, describe the form of an instrument presently being devised, and suggest research uses of the instrument. (Author/LAA)