The present study uses observational assessment of 66 two-parent families working and playing together when their eldest child is in kindergarten and again in ninth grade to identify distinct patterns of family functioning derived from structural family systems theory. Whereas concurrent assessment of the relationship between family type and adolescents' school behavior was not significant, significant prospective longitudinal relationships between family type assessed in early childhood and ninth-grade school behavior was indicated. Kindergarteners whose families were primarily characterized by a strong mother-child alliance were less academically competent, more aggressive/inattentive, and more anxious/depressed/withdrawn at school 9 years later when they were in ninth grade than their peers in more cohesive or father-child allied families. Key Words: adolescence, adolescents and families, developmental psychopathology, early childhood, family interaction. The present study investigated how triadic-level observations of family functioning change from early childhood to adolescence and how family functioning at each of these time points is linked to ninth graders' school adjustment. Previous research investigating linkages between whole-family functioning (interaction among mothers, fathers, and children) and children's behavior finds adolescents' perceptions of family cohesion to be correlated with depression (Unger, Brown, Tressell, & Ellis McLeod, 2000) and academic achievement (Unger, McLeod, Brown, & Tressell, 2000). The vast majority of studies linking family functioning and adolescent functioning, however, are limited in three important ways. First, family research seldom includes triadic-level observation of family functioning (Wagner & Reiss, 1995), relying instead on self-report or observation of family dyads as a means of assessing family functioning (McHaIe & Cowan, 1996). Second, a significant gap exists between clinical family psychology and family research in the way family functioning is labeled and assessed. Clinical family psychologists often use family typologies to identify theoretically meaningful differences among families (Olson et al., 1983). Few studies in the family research literature, however, use typologies to differentiate families, instead assessing family functioning across a series of individual dimensions such as expressiveness or adaptation. Third, family research rarely examines observed family functioning over time. The result is that we have little systematic data to document the way family functioning shifts across development. The present study adds to the existing family research literature by investigating how triadic-level observations of family typologies change from early childhood to adolescence and by investigating how family functioning at each of these time points is linked to ninth graders' behavior at school. TRIADIC-LEVEL FAMILY FUNCTIONING Although many differences exist among family systems theories, one common thread is that observation or assessment of various family subsystems (i.e., parts of the family system such as the dyadic mother-child relationship) is not the same as observing or assessing the family system when the whole family is together (McHaIe & Fivaz-Depeursinge, 1999; Minuchin, 1974). Despite empirical support for clinical family systems theories advocating that assessment of the entire family system (e.g., mother, father, child) is different from, and as important as, assessment of the various parts of a family (e.g., dyadic family subsystems; see Johnson, Cowan, & Cowan, 1999), the majority of family research continues to rely almost exclusively on either the assessment of marital and parent-child dyadic relationships (i.e., mother-father, mother-child, and father-child dyads) or self-report as a method of evaluating family functioning. In an effort to move beyond the dyad and toward a better understanding of the complexities involved in whole-family interaction, the present study assesses family triads (mother-father-child). …