(1) Background: Despite the recognized importance of the patient-doctor relationship (PDR) for pediatric diabetes management, the literature presents diverse and emerging findings regarding its impact on treatment outcomes for children with type 1 diabetes (T1D). (2) Methods: Using a meta-analytic approach, a comprehensive search for relevant studies was conducted across major databases, from the earliest study to June 2024. Inclusion criteria were studies on PDR and T1D outcomes in underaged individuals, providing quantitative results. (3) Results: Fifteen reports were included, showing a small but significant overall effect size (r = 0.165, < 0.05) of PDR on T1D outcomes. Moderator analyses revealed significant associations from elements of PDR, duration of diagnosis, outcome assessment methods, information reporters, and being Caucasian. Demographic variables like gender, age, not being Caucasian, and caregiver's marital status did not significantly impact the association. Specific elements of PDR, such as clinician's objectives, communication, partnership, respect, and supportive care, showed significant positive effect sizes, while telecommunication did not. (4) Conclusions: A strong PDR is essential for managing diabetes in children, particularly in the early years of diagnosis. Future studies should use quantitative designs and include diverse demographics to better understand PDR's connection to T1D outcomes.