Research examining the equivalence of paper and computer-based adult mental health measures has found mixed results, and this issue has not been explored for child self-report measures. Results from adult studies cannot be generalized to young people, especially taking into consideration research indicating that current generations are more comfortable disclosing sensitive information on computer-based media. This paper investigates the psychometric equivalence of the paper (N = 777) and computer (N = 777) formats of a child and adolescent self-report mental health measure, “Me and My School” (M&MS), completed by school pupils aged 8–14 years. Common practice in equivalence testing has been to use scale-level analysis and factor structure equivalence; the limitation being inability to assess format-based differences at the item-level. We conduct differential item functioning (DIF) analysis to assess whether item-response probability is different based on survey format. Results demonstrate that young people completing the M&MS on paper have lower scale-level overall scores. However, DIF analyses indicate that this difference is not explained by item-level probabilities. The results suggest that survey format equivalence testing of other widely used child and adolescent mental health measures may be necessary before data from different formats are directly compared or combined.