Non-suicidal self-injury (NSSI) is a destructive act to oneself that may be related to low self-esteem. However, little is known about the nature of this relationship in adulthood. Therefore, this review synthesized the available literature. Articles were independently identified and risk of bias assessed by two reviewers searching PsycINFO, CINAHL, Medline and Web of Science databases. Inclusion criteria were: (1) a mean sample age of eighteen years or over (2) full manuscripts available in English (3) assessment(s) of NSSI (4) assessment(s) of self-esteem. Nineteen studies were identified and indicated a significant relationship between low self-esteem and NSSI. Results suggested that although low self-esteem and NSSI are related, there are a number of factors which also influence this relationship. It will be important for clinicians to consider the impact of self-esteem in those seeking support for NSSI. Further research should undertake longitudinal research to better understand the self-esteem and NSSI relationship.