Mild traumatic brain injuries (TBI) are commonly sustained by children and adolescents. An extensive literature documents the reciprocal relationship between family functioning and outcomes of childhood moderate and severe TBI, however, the influence of parental and family functioning on children’s post-concussive symptoms (PCS) after mild TBI is not well understood. The goal of this dissertation was to examine the influence of parental and family functioning on PCS after mild TBI. Study 1 consists of a scoping review that examined the existing research on the relationship between parental and family functioning and pediatric mild TBI to determine relevant parental and family factors, summarize findings, and identify areas for further research. Study 2 consists of an original research study that aimed to identify distinct trajectories of PCS after mild TBI in 8- to 16-year-old children and to examine their association with parental and family functioning, as compared to children with orthopedic injuries (OI). Study 1 identified 15 articles that address three questions: (1) Does mild TBI result in more parental distress or poorer family functioning than other injuries?; (2) Does pre-injury or acute parental distress and family functioning predict PCS after mild TBI?; and (3) Does acute PCS predict later parental distress and family functioning? Overall, findings were mixed, although the available evidence suggests that parent and family functioning may have an important, perhaps bidirectional, association with PCS after pediatric mild TBI. Study 2 employed group-based multi-trajectory modeling to classify children into distinct trajectories of child- and parent-reported cognitive and somatic PCS across the first 6 months post-injury and to examine parental and family functioning as predictors of those trajectories. Several parental and family factors were identified as significant predictors of trajectory membership after mild TBI, including parental adjustment, protectiveness, and social support. Study 2 demonstrates that better parental functioning tends to be associated with a more rapid recovery for children with mild TBI. Identification of different symptom trajectories and the influence of parental and family functioning as predictors of those trajectories provides guidance in developing family-based treatments and enabling the targeting of those treatments to children at risk for poor recovery.