A Self-Concept Scale for Adolescents based on Havighurst's Developmental Tasks for Youth was constructed to reflect adolescents' perceptions of their ability to achieve these tasks in relation to personal abilities, the abilities of others, and the criteria for successful task completion. A validity and reliability study showed the scale to be both valid and reliable. The scale was administered to 280 Caucasian and 256 Indian adolescents to compare the effects of sex, age, grade level, grade point average (GPA), and social class on their perceptions of their ability to achieve Havighurst's developmental tasks. Sex, age, and grade level were not significant factors in the achievement of Havighurst's Developmental Tasks by Caucasian adolescents. For Indian adolescents, sex, age and social class were not significant. GPA had a notable effect on the Indians' perceptions of their ability to achieve the tasks; social class had much the same effect on Caucasian adolescents. This difference may be explained by cultural and environmental influences. (The Self-Concept Scale for Adolescents and a report of the validity and reliability study of the scale are included.) (Author/NRB)