Purpose — Waqf unit trust funds are a form of value-based impact investing that combines financial investment with philanthropic goals through waqf (Islamic endowment). This study uses the theory of planned behaviour (TPB) to investigate the factors that influence people’s intentions to participate in waqf unit trust funds in Malaysia. Furthermore, the study investigates the function of religion as a moderator in predicting an individual’s intention to engage in waqf unit trust funds. Design/Methodology/Approach — Four hundred and four completed survey questionnaires have been obtained. Descriptive analysis and Partial Least Square–Structural Equation Modelling (PLS-SEM) are performed to analyse the data. Findings — The findings show that an individual’s intention to engage in waqf unit trust funds is influenced by attitude, subjective norms, perceived behaviour control, and moral norms. Furthermore, religiosity influences the relationship between moral norms and the intention to join in waqf unit trust funds. Research Implications and Limitations — Findings from this study which focuses on Muslims’ involvement in recently established waqf unit trust funds can be used by the waqf unit trust managers in Malaysia to develop appropriate marketing strategies in encouraging Muslim participation in waqf unit trust funds. Participation in waqf unit trusts is not limited to Muslims; hence, future studies can be conducted to cover a wider base of respondents among non-Muslims.