Single-sex cooperative, mixed-sex cooperative, and individualistic learning situations were compared to determine if they promoted systematic differences in relationships between male and female students and handicapped and nonhandicapped students. One-hundred-fifty-four 5th-and 6th-grade students were assigned to conditions on a stratified random basis controlling for ability, sex, grade level, homerooms, and handicap. They participated in a study for 45 minutes a day for 21 days in science class. The results indicate that cooperative learning situations, compared with individualistic ones, promoted more positive cross-sex and cross-handicap relationships. Males achieved higher and had more positive attitudes toward science than did females.