<p>Childhood trauma (CT) has long been linked to adverse outcomes, including self-injurious behaviours. The aim of the present study was to examine the relationship between childhood trauma and self-injurious behaviour (SIB), as well as to assess the associational effect of entrapment in the relationship between those two variables. The sample comprised 273 young adults (75.5% women), aged between 19 and 25 years, who were enrolled in an undergraduate degree program at a Portuguese university. An associational model was tested using path analysis with structural equation modelling (SEM). CT was specified as the independent variable, as well as demographic variables correlated with SIB included as covariates, with entrapment specified as the associational variable, and SIB as the dependent variable. Results indicated that 60.1% of participants reported having engaged in at least one SIB at some point in their lifetime. Significant direct effects were found between CT and entrapment, between entrapment and SIB, and between CT and SIB. Additionally, a significant indirect effect was observed in the relationship between CT and SIB. Overall, the findings suggest that entrapment statistically accounts for part of the association between childhood trauma and self-injurious behaviours, contributing to understanding why individuals who experienced a greater number of traumatic events in childhood may be more likely to engage in SIB. However, the cross-sectional design limits causal inference and the ordering between entrapment and SIB cannot be definitively established.</p>