Stigma is an understudied barrier to health care acceptance in pediatric oncology. We sought to explore the stigma experience, including its impact on cancer treatment decision making, and identify strategies to mitigate stigma for patients with osteosarcoma and retinoblastoma in Guatemala, Jordan, and Zimbabwe. Participants included caregivers, adolescent patients (age 12-19 years), and health care clinicians. A semistructured interview guide based on The Health Stigma and Discrimination Framework (HSDF) was adapted for use at each site. Interviews were conducted in English, Spanish, Arabic, or Shona, audio-recorded, translated, and transcribed. Thematic analysis focused on stigma practices, experiences, outcomes, drivers, mitigators, and interventions. We conducted 56 interviews (28 caregivers, 19 health care clinicians, nine patients; 20 in Guatemala, 21 in Jordan, 15 in Zimbabwe). Major themes were organized into categories used to adapt the HSDF to global pediatric cancer care. Themes were described similarly across all sites, ages, and diagnoses, with specific cultural nuances noted. Pediatric cancer stigma was depicted as an isolating and emotional experience beginning at diagnosis and including internalized and associative stigma. Stigma affected decision making and contributed to negative outcomes including delayed diagnosis, treatment abandonment, regret, and psychosocial fragility. Overcoming stigma led to positive outcomes including resilience, treatment adherence, pride, and advocacy. Identified stigma drivers and mitigators were linked to potential interventions. Participants describe a shared stigma experience that transcends geography, cultural context, age, and diagnosis. Stigma manifestations have the potential to impact medical decision making and affect long-term psychological outcomes. Stigma assessment tools and interventions aimed at stigma mitigation including educational initiatives and support groups specific to pediatric cancer should be the focus of future research.