Although non-suicidal self-injury (NNSI), a behavior with a typical onset during adolescence, is a well-researched topic in the international literature and affects numerous adolescents both in clinical and non-clinical populations, it is rarely studied in Hungary. The aim of our paper is to review the historical and cultural background, terms and definitions used in the international and Hungarian literature, the epidemiology, the psychosocial correlates and the theories for possible predictors and functions of NSSI. Terms and definitions for NSSI evolved in international but not in Hungarian literature. Most frequently found functions for NSSI were affect regulation, self-punishment, anti-suicide, anti-dissociation. NSSI is also used to affirm interpersonal boundaries, for sensation seeking and to influence others. Prevalence of NSSI is 15-46% in community and 40-80% in clinical sample in adolescents. Hungarian results on prevalence of NSSI are relatively low in comparison with international data (7-17% in adolescent community sample). NSSI is often associated with psychiatric disorders: DSM-IV Axis I disorders are present in 88% and Axis II disorders are present in 67% of adolescent self-injurer samples. NSSI and suicidal behavior are two different but not independent phenomena: correlation is approximately 50% in community and 70% in clinical population. In conclusion we would like to highlight that NSSI affects numerous adolescents and it is often comorbid with other psychiatric disorders, thus developing adequate Hungarian terminology, increasing the amount of Hungarian studies and the up-to-date knowledge of the clinicians are necessary.