Background: Mirror therapy is a type of intervention aimed at paying the child's attention to perform the physical exercises of the non-affected side by visually stimulating the child's perception. Children with cerebral palsy need to learn strategies and techniques leading to learned non-use of the affected hand. The aim of the study is to assess the effect of a mirror intervention program on hand activity, mastery motivation, and self-esteem among children with cerebral palsy. Research design: A quasi-experimental design was used in this study. The study subjects consisted of 50 children suffering from unilateral spastic cerebral palsy aged 6-12 years old. Setting:  The study was conducted at the specialized outpatient department in Children's Hospital affiliated to Ain Shams University Hospitals, Cairo, Egypt. Tools: The data was collected using 1) Demographic characteristics of the studied children and their parents; 2) Upper Extremity Functional Index; 3) Activities of Daily Living Checklist; 4) Box and Block Test; 4) Dimensions of Mastery Questionnaire; 5) Coopersmith Self-Esteem Inventory. Results: The present study revealed that there was a statistically significant difference pre-, post, and follow-up of the mirror intervention program regarding upper extremity functional index, activity of daily livings, and box and block test with (F test = 48.54, 7.29, 8.51 respectively with P value ≤ 0.05). The study also revealed statistically significant differences in the dimensions of mastery scores, especially during the follow-up assessment after implementing the mirror intervention program (F test = 54.87 with P value ≤ 0.05). Meanwhile, a non-statistically significant difference was noted regarding the Coopersmith self-esteem inventory (F test= 54.87 with P value ˃ 0.05). There were strong positive correlations between study variables. Conclusions. The mirror intervention program had significant changes in hand activity and mastery motivation among children with cerebral palsy, while it did not have a significant effect on children's self-esteem. Recommendation: A longitudinal study should be conducted to assess the impact of a mirror intervention program on a large sample of children with special disabilities related to hand activity, self-esteem, and other psychological aspects.