The purpose of this study was to examine validity and reliability evidence of a questionnaire regarding parents’ beliefs and intentions toward supporting physical activity (PA) participation of their children with disabilities (CWD). A total of 220 parents of CWD in South Korea completed a questionnaire that was developed using the theory of planned behavior (TPB). Exploratory factor analysis revealed that behavioral, control, and normative beliefs accounted for 31.13%, 20.45%, and 19.63% of the total variance of the intention, respectively. Reliability of entire scale was .85 using Cronbach’s alpha. Reliabilities of the 3 beliefs were .86, .82, and .87, respectively. Standard multiple-regression analysis indicated that behavioral and normative beliefs significantly predicted parents’ intention, p < .01. Intention was a significant predictor of parents’ behavior, p < .01. The results of this study indicated that the TPB can be useful to examine parental support for PA participation of their CWD.