To examine specialist mental health service, hospital discharge, and pharmaceutical dispensing data for emotional conditions (anxiety, depression), substance use, and self-harm for Māori compared to non-Māori/non-Pasifika (NMNP) youth.A novel population-level case identification method using New Zealand's Integrated Data Infrastructure for 232,845 Māori and 627,891 NMNP aged 10-24 years. Descriptive statistics on mental health conditions were generated and stratified by Māori/NMNP. Unadjusted and adjusted risk ratios (RRs) of mental health conditions were generated using generalised linear regression.Māori were less likely to be identified for anxiety (ARR=0.88; 95% CI 0.85-0.90) or depression (ARR=0.92; 95% CI 0.90-0.95) than NMNP. They were more likely to be identified for substance problems (ARR)=2.66; 95% CI 2.60-2.71) and self-harm (ARR=1.56; 95% CI 1.50-1.63). Māori living in high deprivation areas were significantly more likely to be identified for substance problems, but less likely for emotional conditions, than Māori in least deprived areas.Despite known high levels of mental health concerns for rangatahi Māori, administrative data suggests significant under-reporting, assessment, and treatment of emotional conditions relative to NMNP. These differences were exacerbated by deprivation. Māori were more likely to be referred to services for externalised symptoms of distress (substance use and self-harm).