This paper develops a rationale for a three dimensional model of nonintellectual behavior of children and supports the rationale with a review of relevant theoretical and empirical work. The tenability of the model and its relationship to early reading achievement is then explored. Dimensions derived from a cluster analysis of the "Pupil Behavior Rating Scale" support the conceptual model by defining an adaptation dimension, an interpersonal dimension, and an intrapersonal dimension. The relationship of each of the dimensions to reading achievement of children when they are in first and second grade showed that the adaptation dimension was a crucial contributor to reading achievement level. Furthermore, the significant unique contribution of this dimension to reading achievement when the effects of sex, socioeconomic level, ethnic status, and cognitive functioning were controlled indicates that levels of adaptation in children need to be further explored as prerequisites to success in early reading programs. (Author)