Purpose: This study will examine how attitudes, subjective norms, and perceived behavioural control (PBC) affect sustainable waste management behaviour (SWMB) in Sabah, Malaysia's palm oil mills. Theoretical framework: This study has adopted the Theory of Planned Behaviour (TPB) that serves as the primary theory in this research, which utilized a conceptual framework. Design/ methodology/approach: This study employed a probability sampling where a series of questionnaires has been distributed to members of the upper management of 133 oil palm mills in Sabah were used to gather the data, which was then processed using Smart-PLS V4. Findings: According to the findings of this research, subjective norms and perceived behavioural control are important factors that contribute to SWMB adaptation in oil palm mills. The most significant association was found to be between subjective norms and SWMB. On the other hand, attitudes have been reported to have no substantial influence on environmentally responsible waste management behaviours. Research, Practical & Social Implications: To put it more succinctly, this study will give a framework for the regulation of palm oil waste in Malaysia through the establishment of a more effective legal and regulatory environment in this area.