Objective Children with amplified musculoskeletal pain (AMPS) experience significant functional disability, with impairment in their ability to participate in age-appropriate activities of daily living. Parental factors play an important role in a child’s pain symptoms and treatment outcomes, with parental pain catastrophizing and protective behaviors linked to several maladaptive outcomes for children. Aims of the current study were to examine how parental pain catastrophizing, child pain catastrophizing, and parental protective behaviors longitudinally impacted functional disability for children with AMPS. Methods Archival data were examined from parent-child dyads presenting to a tertiary pain clinic for treatment of AMPS. Over 1 year, parents completed measures assessing the level of pain catastrophizing, common behavioral responses to child pain, and child functional disability. Children completed measures of pain catastrophizing and functional disability. Measures were collected at initial evaluation, 6-months, and 12-months. Latent growth models (LGM) were conducted to examine how to study variables longitudinally impacted the rate of change in child functional disability. Results Examining a comprehensive LGM of study variables, parental catastrophizing emerged as the sole contributing factor to slower improvement in functional disability. Conclusions The strong influence of parental pain catastrophizing on functional disability may relate to parents limiting behaviors that promote adaptive coping in children with pain. As such, parents who catastrophize may benefit from specific interventions to increase their use of adaptive behavioral responses, such as redirecting children to complete functional activities and encouraging the use of positive coping skills for pain-related distress.