Musculoskeletal pain has become a major symptomatic complaint among children and adolescents and is increasingly occurring at a younger age. This systematic review was done to evaluate the evidence for the contribution of posture and psychosocial factors to the development of upper quadrant musculoskeletal pain in children and adolescents. The review describes the measurement tools used to assess musculoskeletal pain, sitting posture, and psychosocial factors. Two independent reviewers searched seven databases for observational studies that included prospective and cross-sectional study designs. Ten studies were extracted and assessed by two reviewers using the Critical Appraisal Form-Quantitative Studies (Law et al, 1998). The studies measured upper quadrant musculoskeletal pain as an outcome measure. Five studies evaluated sitting posture and found an association between the duration of static sitting and upper quadrant musculoskeletal pain. Six studies measured psychosocial factors of which depression, stress, and psychosomatic symptoms were the factors most commonly found to influence the development of upper quadrant musculoskeletal pain. The eligible studies used different pain measurement tools and different measurement tools to assess sitting posture and psychosocial factors. This review concludes that the duration of sitting posture and psychosocial factors may influence the experience of musculoskeletal pain among children and adolescents.