AIM: Given Singapore's distinct multicultural identity, this study examined the hypotheses that there may be ethnic group differences in diagnosis and outcomes in autistic children in Singapore. METHODS: Retrospective data were obtained from medical records of all children born between 2008 and 2011 who were diagnosed with clinical or confirmed autism. One-way ANOVAs and regression analyses were used to analyze data. RESULTS: Data from 2577 medical records were extracted. There were more boys (82.5%) and ethnic group distribution was Chinese (67%), Malay (14%), Indian (10%), and Others (10%). Chinese children were more likely to present at a developmental clinic with concerns 3-4 months younger compared to Malay children and those from Other Races (F(3, 2038) = 9.58, p <
.001, Cohen's F = 0.12). Chinese children were also more likely to receive an autism diagnosis approximately 3 months younger compared to Malay children. Fewer autistic Chinese children were diagnosed with co-occurring intellectual disability (13.1%) while there were almost twice more Malay children than expected with co-occurring intellectual disability (29.9%) (χ CONCLUSION: Several significant ethnic group differences in autistic children in Singapore exist that warrant more investigation into possible causes and support systems needed, with implications for other ethnically diverse nations.