Adolescents' feelings of belongingness were investigated by this study, in which 349 high school students participated. Independent variables for family structure, quality of family life, gender, classification, and length of residency were investigated. The dependent variable was scores from the Psychological Sense of School Membership scale. Results appear to support the following generalizations: (1) seniors have greater feelings of belonging than freshmen; (2) students who had lived in the community all their lives, or two or more years, have greater feelings of belonging than those who lived in the community less than two years; (3) family structure and quality of family life should be interpreted concurrently; and (4) students have above-typical feelings of belonging. Seven appendices present facsimiles of letters to school officials, memos to seminar teachers, instructions and the demographic sheet giving to each student participant, the Psychological Sense of School Membership Inventory, and the Personal Attribute Inventory--Family. Contains 40 references. (TS)