Palm oil is relatively inexpensive, versatile, and popular, generating great economic value for Southeast Asian countries. However, the growing demand for palm oil is leading to deforestation and biodiversity loss. The current study is the first to employ a capability-opportunity-motivation (COM-B) framework in green consumerism, to determine which capability, opportunity, and motivation factors strongly predict the intentional purchasing of sustainable palm oil products by Australian consumers (N = 781). Exploratory factor analysis revealed four main types of predictors of SPO purchasing–Pro-Green Consumption Attitudes, Demotivating Beliefs, Knowledge and Awareness, and Perceived Product Availability. Multiple regression revealed that these four factors explained 50% of the variability in SPO purchasing behaviour, out of which Knowledge and Awareness accounted for 18% of the unique variance. Perceived Product Availability and Pro-Green Consumption Attitudes were also significant predictors but accounted for only 2% and 1% of unique variance, respectively. These results provide a valuable foundation for designing behaviour change interventions to increase consumer demand for sustainable palm oil products.