This study uses New Zealand secondary school students to assess the effects of coeducation on student attitudes and behaviors related to academic motivation and achievement. Subjects were 1225 students in their third and fourth years of secondary school. Part of the sample attended coeducational schools, and part attended single-sex schools. Questionnaires were given to all students. Chi-square analysis of responses indicates significant differences between responses of students in the coed schools and those in the single-sex schools in scholastic activities and attitudes, presitge and popularity, peer influences, and self-regard. Students from single-sex schools tend to value scholastic achievement and sports participation more than do coed students. Single-sex school students also seem less preoccupied by "rating and dating." The author suggests that a re-examination of the value of coeducation may be in order. (MPJ)