This study examines previously untested variables that influence social loafing in professional and technical communication group projects by determining the influence of communication quality and task cohesion on social loafing. A set-up factors model, which included group size, peer review, project scope, and method of team formation, was also tested for means of comparison. The results indicated the communication quality and task cohesion model significantly reduced social loafing, explaining 53% of the variance in social loafing. The model of set-up factors only explained about 4% of the variance. The article discusses instructional strategies that foster quality communication to reduce loafing.