Problem behavior during hallway transitions are likely for several reasons: (a) students are in closer proximity of each other, (b) teacher monitoring of students is more difficult and/or (c) there are fewer competing behavior options that have been reinforced (Myerson & Hale, 1984). The current study compared the effects of small- and large-group dependent group contingencies on problem behavior during hallway transitions. The results of the study produced equivocal findings with respect to the impact of group contingencies. Specifically, large-group dependent group contingencies did not result in lower levels of problem behavior relative to the baseline condition of the intervention phase, while small-group dependent group contingencies did result in lower levels of problem behavior relative to the baseline condition of intervention. In addition, the results indicated that the small-group dependent group contingency clearly resulted in reduced problem behavior relative to the large-group dependent group contingency for two classes. Implications and future research are discussed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]