This study examines the feasibility and acceptability of ‘Speak out against racism (SOAR)’ program to promote effective bystander responses to racism in Australian primary schools. A mixed-methods, quasi-experimental design was used. Students in Years 5 and 6 (10-12 years) across six schools completed surveys pre- and post-intervention (N=645; 52% female, 6% Indigenous, 10% Middle Eastern, African, Latinx, Pacific Islander, 21% Asian, 52% Anglo/European). Quantitative data showed student prosocial skills and teacher inter-racial climate improved in intervention schools compared to comparison schools. Qualitative data highlighted teacher attitudinal and behaviour change regarding racism, and student reduced interpersonal racial discrimination, improved peer prosocial norms, commitment to anti-racism, knowledge of proactive bystander responses and confidence and self-efficacy to intervene to address racism.