Parental trust in medical researchers is a commonly cited barrier to their child’s participation in clinical research. Yet, there is little understanding of factors influencing parental trust to be implemented in interventions to address their concerns. This study seeks to identify psychosocial and modifying factors influencing parental trust in medical researchers to improve child and adolescent patients clinical trial participation, and potentially their health outcomes. We conducted a cross-sectional study with 307 parents. Multiple ordinary linear (OLS) regression was conducted to determine: (1) psychosocial and modifying factors associated with parental trust; and (2) perceived advantages and disadvantages associated with parental trust. Parent’s race (White) (β = .343, p < .001), higher education level (β = .409, p < .001), higher perceived advantages of adolescent clinical trials (β = .142, p < .001), and lower perceived disadvantages of adolescent clinical trials (β = −.337, p = .001) were the most significant predictors of higher levels of parental trust in medical researchers. Parents who were African American and had lower education levels expressed lower levels of trust in medical researchers. Education on the benefits of clinical trials could reduce parents’ apprehension towards their child’s participation in clinical trials. Results support the development of a clinical trial education program for parents to improve their trust in medical researchers.