This study investigated the impact of a sequence of social relationship activities on regard for classmates and teammates in middle school (grade 7) mathematics classes using cooperative learning. The sample consisted of 184 students (55% Hispanic American, 27% White, 14% Black, and 3% Asian American) in a city in Los Angeles County (California). Two teachers each taught three classes; each teacher taught two experimental treatment (cooperative learning) classes and one conventional (comparison) class. Activities were sequenced and related to the following stages of group development: (1) class-building; (2) preparation for group work/team-building; (3) communication; and (4) cooperation and helping behaviors. Students in experimental groups also received instruction in effective explaining and problem solving. Overall, the sequence of interventions was effective in increasing students' regard for one another. Class-building increased students' regard for classmates, and team-building and activities to prepare for group work were effective in increasing students' regard for teammates and cross-ethnic and cross-gender regard. The differences between classes demonstrate how cooperative learning can differ in practice even when teachers have the same instructions and students have the same activities. Statistical data are presented in 12 tables. A 33-item list of references is included. (SLD)