The objective of this study was to determine if 5-dog and 3-dog play groups had observable effects on-kennel arousal behavioral levels. This study was performed at the Animal Rescue League (ARL) of Iowa, located in Des Moines. A total of 36 dogs of mixed sex, breed, and age were observed. Two treatments were compared (1) 3-dog groups (n = 24) and (2) 5-dog groups (n = 12). All dogs included in this study had never been exposed to a play group before at the ARL-IA. Each dog was observed before play group (baseline) at 9 am and after play group (after) at 11 am respectively. Play sessions were held between 9 and10 am. Two dogs, one from each treatment, was removed for aggression issues and euthanized. Their data will not be presented. The observer watched one dog at a time, and stood in front of the kennel for 10 s, observing each dog and recording its behavior. Dogs allocated to both treatments during baseline all scored a recording level one, indicating a dog that was not displaying overt signs of behavioral anxiety in the kennel. When looking within categories, there were improvements within this category for in kennel behaviors between baseline and after. In the 5-dog play group, dogs displayed less barking (<30%) and jumping (<25%). The dogs in the 3-dog treatment showed improvements across all measures except for position in kennel, where no change was observed. In conclusion, both treatments showed improvement within recording level one for in-kennel behaviors and a decrease in in-kennel arousal levels post-play group. However, dogs displaying more severe in-kennel behavior(s) should be included in a future study to see if play groups improve in-kennel behavioral arousal levels resulting in improved adoptability and overall dog well-being.