This paper reports on a study of 31 Japanese-American adolescents enrolled in a Saturday Japanese heritage school (JHL) in Los Angeles. The study examined the relationship of the participants' sense of ethnic identity, attitudes toward the JHL school and self-assessed proficiency in Japanese. The major finding of the study, consistent with previous research, was that the variables examined were significantly related. The results also revealed that the older students had a stronger sense of identity as Japanese than the younger students. Moreover, in six months, positive gains were observed in Japanese ethnic identity as Japanese, attitudes toward their JHL school, and self-assessed Japanese proficiency. (Contains 6 tables and 1 note.)