Purpose: To understand factors contributing to therapy success, this study investigated the role of parents' temperament and the fit between parents' temperament and parent-reported child behavior problems in therapy outcomes across two therapy types. Method: A total of 177 children who stutter and their parents were included in this study. Data from 149 children were present at the follow-up. Children received either Lidcombe Program (LP) or Rotterdam Evaluation Study of Stuttering Therapy randomized trial--Demands and Capacities Model (RESTART-DCM) therapy. Parents' temperaments and children's behaviors were measured at baseline. At 18 months of therapy post-onset (T4) and 5 years later (T5), the children's remittance or persistence in stuttering was assessed. Results: High parental novelty seeking and high harm avoidance were associated with transient stuttering at T4 in the entire sample. Looking across therapies, novelty seeking remained significant in the RESTART-DCM group at T4, whereas in the LP group, significant associations were observed for reward dependence (at T4 and T5) and persistence (at T4). Meanwhile, none of the parent-child fits were associated with therapy outcome. Conclusions: The results suggest that for preschoolers receiving treatment, parents who tend to seek novelty and exploration, as well as those with greater vigilance toward harm, have a positive impact on therapy success. In contrast, socially dependent parents might have a negative impact on therapy success in children receiving LP treatment, whereas diligent parents could serve as a protective factor in this therapy. These exploratory results should be interpreted with caution, and future research will be crucial to confirm and further interpret these results.