This paper attempts to analyse the investment behaviour in the retail green sukuk (RGS) issued by the Indonesian government. The research framework is based on the Theory of Planned Behaviour (TPB), while the Partial Least Square-Structural Equation Modelling (PLS) was employed as a research method. Online questionnaires were distributed to potential retail investors. A total of 113 respondents met the requirements and were used as the sample in this research. The findings show that decision to invest in RGS is influenced by intention and perceived behavioural control (PBC). Meanwhile, attitude and subjective norms have significant influence on the intention to invest in the RGS. Attitude is found as the strongest predictor of intention and is influenced by knowledge about RGS, environmental awareness and religiosity. Based on these findings, it is recommended that the government should intensify campaigns about sukuk and green issues. The promotion of RGS should be targeted to the religious individual/community with sufficient literacy of sukuk and awareness of the green issues.