The aim of the study was to examine the effect of the Online Intervention Program implemented during the COVID-19 period on the quality of life (QoL) and physical activity (PA) levels of individuals with intellectual disability (ID) and their mothers. The experimental method was used in this study. A total of 184 people, 92 individuals with intellectual disability and their mothers participated in the study. By random assignment method, 40 participants with ID and their mothers were assigned to the experimental group (EG) and 52 participants and their mothers were assigned to the control group (CG). The participants with ID in the EG participated in PA and music activities for 60 minutes a day, three days a week for 12 weeks, and the mothers participated in a psychological counseling program for 80 minutes a day, one day a week. “Personal information form” and “WHOQOL-BREF Turkish version” for mothers, “WHOQOL-BREF & Intellectual Disability Module” for individuals with ID, and “International Physical Activity Questionnaire” for mothers and individuals with ID were used as data collection tools. As a result of the analyses, it was found that the mothers and the individuals with ID who participated in the online intervention program maintained their PA levels, the mothers showed a significant increase in all sub-dimensions of QoL, and the individuals with ID had a partial increase in their QoL.