Research has documented that collaborative learning groups improve student learning and increase the likelihood that students will have positive attitudes about both the subject matter and their peers. However, researchers know much less about how collaborative learning groups may influence student behavior and the extent to which their utility extends to testing as well as projects and papers. In an effort to address these gaps, we used quasi-experimental and survey data to examine the effects of collaborative testing on Introduction to Sociology students' learning, behavior, and attitudes. Findings indicate that collaborative testing improved students' behavior and attitudes. In comparison to a control group, students who participated in collaborative testing reported completing more of their assigned readings and had improved attitudes toward their learning, the testing process, and sociology. (Contains 3 tables.)