Background/aim: Occupational therapists use different models and measurements for assessing children with attention-deficit/hyperactivity disorder (ADHD). One of those measurements is the Child Occupational Self-Assessment. In this study, concurrent validity of the Child Occupational Self-Assessment with Pediatric Quality of Life was tested in children with ADHD. Methods: A correlational study was conducted. The Child Occupational Self-Assessment and Pediatric Quality of Life were filled by 128 children with ADHD aged between 8 and 11 years. Findings: The results indicated that in competency subscale the highest correlation coefficient was for the total score of Pediatric Quality of Life ( r = 0.56, p < 0.01) and the lowest was for social performance ( r = −0.44, p < 0.01). The highest and lowest correlation coefficient in value subscale were for the total score ( r = −0.46, p < 0.01) and emotional performance of Pediatric Quality of Life ( r = −0.34, p < 0.01), respectively. Conclusions: The Child Occupational Self-Assessment has an acceptable concurrent validity with Pediatric Quality of Life. It can be a suitable measurement for assessing of children with ADHD.