The purpose of this study was to examine the experiences and the courses of change among individuals with disabilities in sheltered workshops, during the cooperative group art therapy designed for sociality improvement. The study participants were three individuals with intellectual disabilities and two individuals with brain lesions at the sheltered workshops in the S welfare center located in D city. Twelve group art therapy sessions were conducted, once or twice a week for 60 minutes per session, from July 9, 2020, to August 20, 2020. The art therapy program was designed based on the learning together model from the cooperative learning theory that maximizes positive interactions between group members through cooperation. As a result, a total of six main themes and twelve sub-themes were derived; the six main themes were, “showing difficulty and fear of art expression,” “difficulty in understanding and recognizing the concept of group and cooperation,” “starting to interact and have certain understanding of group and cooperation,” “beginning to share opinions necessary for activities,” “recognizing others and the manners of group interaction becoming flexible,” and “showing active participation in sharing experiences and opinions on the topic of the activity.” This study is significant because it shows that individuals with disabilities in the sheltered workshops can experience positive changes by improving their self-expressive ability and acquired social skills through cooperative group art therapy.