Background: Play therapy is now considered an important part of physical therapy programs in children with cerebral palsy. Objective: The purpose of this study was to investigate the effectiveness of play therapy along with conventional physical therapy on gross manual dexterity in children with spastic hemiparetic cerebral palsy. Participants and Methods: 30 children with spastic hemiparetic cerebral palsy were divided into two equal groups; a control group received conventional physical therapy and a study group received play therapy in addition to the conventional physical therapy. The treatment was given 3 days per week for 6 successive weeks for both groups. Box and Block Test was used to measure gross manual dexterity of the affected upper extremity before as well as after intervention. Results: There is a non-significant difference between the control and study groups before as well as after intervention. However, there is a significant difference in each group when comparing between pre and post measures. The percentage of improvement in the gross manual dexterity is about 16.7% in the control group and about 46.4% in the study group. Conclusion: Play therapy combined with the conventional physical therapy may have a significant effect in improving gross manual dexterity in children with spastic hemiparetic cerebral palsy.