Abstract Objectives: Youth self-harm (SH) is viewed as a public health concern and one of the main reasons for urgent psychiatry assessment. This systematic review sought to establish prevalence of SH among youth in Ireland. Methods: A systematic review using pre-defined search terms was conducted (Jan 1980–March 2024). Results: From a total of 204 papers identified, 18 were included. Significant variation in rates of SH was found. Limiting data to adolescent years (15–18), best estimates for overall lifetime rates of SH ranged from 1.5% (when rates of SH were reported based on a two-stage study design), to 23% (where SH was limited to non-suicidal SH). SH was typically higher in females, impulsive in nature, and occurred in the home setting. Whilst almost half of youth sought help before (43.7%) or after (49.8%) the SH episode, this was most often to a friend or family member. Overall rates of professional help seeking were low. Conclusions: Robust studies using clear definitions of terms, separately capturing SH with and without suicidal intent, and distinguishing SH in the context of a mental illness, are required to inform service developments. Given the frequent occurrence of SH among youth accompanied by predominance of help seeking via friends and family, it is imperative that psychoeducation is delivered to families and peers. Out of hours community and specialist mental health services are essential to address this important issue.