This field study investigated the application of cooperative, competitive, and individualistic goal structures in classroom use of computer math games and its impact on students' math performance and math learning attitudes. One hundred and sixty 5th-grade students were recruited and randomly assigned to Teams-Games-Tournament cooperative gaming, interpersonal competitive gaming, individualistic gaming, and the control group. A state-standards-based math exam and an inventory on attitudes toward mathematics were used in pretest and posttest. Students' gender and socioeconomic status were examined as the moderating variables. Results indicated that even though there was not a significant effect of classroom goal structure in reinforcing computer gaming for math test performance, game-based learning in cooperative goal structure was most effective in promoting positive math attitudes. It was also found that students with different socioeconomic statuses were influenced differently by gaming within alternative goal structures.