Objectives: To examine the mediating effect of general self-efficacy on the relationship between the source of meaning in life (SML) and prosocial behaviours in vocational college nursing students. Methods: Between March and June 2019, a cross-sectional descriptive study was conducted, and 799 nursing students from three vocational colleges completed the Source of Meaning in Life Scale, General Self-Efficacy Scale and Prosocial Behaviours Scale. Data were analyzed using structural equation modelling and statistical analysis by SPSS (version 23.0, IBM). Results: The average SML, general self-efficacy and prosocial behaviours scores of the 799 nursing students were 6.43±0.83, 2.48±0.59 and 3.69±0.62, respectively. Correlation analysis showed that SML, general self-efficacy and prosocial behaviours were positively correlated (P<0.01). General self-efficacy partially mediated the relationship between SML and prosocial behaviours (P<0.01); this mediating effect contributed 22.97% of the total effect and explained 17.6% of the variance in the dependent variable. Conclusions: Educators should focus on cultivating nursing students' cognition and experience of meaning in life and their efficacy in life, study and work, which can improve students' "people-oriented" service and prosocial behaviour and the quality of nursing services. [ABSTRACT FROM AUTHOR]