Effective parent functioning is a key predictor of functional outcomes for children with persistent pain. It is therefore important to identify factors that support or limit functioning in parents of these children. Child and parent attachment and child sensory processing patterns have been identified as risk-factors for parent functioning in healthy samples. Our study extends current research by examining whether parent and child attachment patterns and child sensory processing patterns are related to parent functioning in families of children with persistent pain. Using a cross-sectional design, data was collected at a tertiary pain management clinic from 98 parent-child dyads (i.e., a child or adolescent with persistent pain and one parent). Standardized questionnaires were used to assess parent and child attachment patterns, child sensory processing patterns, child pain intensity, and eight domains of parent functioning. Regression analyses revealed that parent attachment avoidance was significantly related to poorer overall parent functioning and three functioning domains: depression, partner relationship, and leisure. Child attachment avoidance was related to higher parental strain and the use of fewer protective parenting behaviors. Parent and child attachment anxiety and child sensory processing patterns were not significantly related to parent functioning. Findings suggest that parent and child attachment avoidance warrant further consideration with regards to parent functioning in clinical settings where children present with persistent pain. This may aid in identifying parents who are at-risk of poorer functioning and could guide the use of attachment-informed interventions for families of children with persistent pain.