Children with cerebral palsy have difficulty to sit, stand, walk, run and jump independently. Therapy is an important factor in improving these aspects, and if applied in early intervention treatments, when the child is growing, it could have many benefits. These therapies require intensive and extended sessions, which in turn demand dedication and effort. New strategies that provide interesting and motivating interventions are often incorporated to improve the participation and performance of the children in the therapies. Therapies using social assistive robots can be alternative and complementary methods to promote the participation and motivation of children with cerebral palsy. The objective of this work is to validate the effectiveness of a 16-session physical therapy program to improve the participation and fulfillment of therapeutic objectives on an 8 year-old boy with dyskinetic cerebral palsy for motor learning to walk using a social assistive robot. The therapy program was carried out through a methodological proposal that uses SMART objectives (Specific, Measurable, Achievable, Realistic and Timed), Goal-Directed Therapy (GDT) and its evaluation through Goal Attainment Scaling (GAS). A NAO robot was used as a social assistive robot to support a physical therapy for a child with cerebral palsy. In this work, it was observed that the motivation generated by the interaction with the social assistive robot facilitated the persistence in the walking and the fulfillment of the objectives. Using humanoid robots as social assistive robots may benefit therapeutic processes on children with motor disabilities. The methodology developed provides a formal way to achieve objectives in therapeutic processes for children with cerebral palsy.Implications for rehabilitationIt requires researchers to conduct more studies to validate the potential of the use of social robots in therapeutic interventions that promote development in children with motor disabilities, such as cerebral palsy.Promoting the use of new technologies in therapeutic processes such as humanoid robots allows us to create new strategies to know the impact of this technology in the area of rehabilitation.The use of formal methodologies focused on the patient, along with multidisciplinary teams, could increase the possibilities of using social robots to improve cognitive and motor outcomes in children with cerebral palsy.The formulation of SMART objectives and their quantification through the GAS scale can be used as recommendations to improve the formulation of goals in therapeutic interventions for children with cerebral palsy.