Many university students who engage in self-harm do not seek professional help. Thus, it is imperative to identify the factors that facilitate and prohibit professional help-seeking for self-harm. The theory of planned behaviour was used to examine social-cognitive variables, namely attitudes, subjective norms, and perceived behavioural control, as predictors of professional help-seeking for self-harm. More favourable attitudes toward professional help-seeking for self-harm predicted greater intent to seek this help among individuals with a history of self-harm; this relation increased as a function of greater self-harm frequency. Furthermore, university students who perceived advice from friends as encouraging of seeking professional help for self-harm endorsed greater intent to seek professional help. Findings highlight the importance of targeting attitudes toward professional help for self-harm in prevention and intervention programs with theoretical, empirical, and clinical implications discussed.