<p>This study investigates the perceptions and attitudes of construction professionals toward material waste minimisation as a key component of the circular economy (CE) framework using the Theory of Planned Behaviour (TPB) as an explanatory lens. The research focuses on their awareness of waste issues, attitudes toward reduction strategies, and perception of the benefits and challenges of waste minimisation in the CE context. A qualitative approach was adopted, using semi-structured interviews with 65 construction professionals across ten medium-to-large scale building projects in Lagos, Nigeria. This approach provided in-depth insights into professionals’ awareness of waste impacts, attitudinal orientations towards waste reduction, and perceptions of the importance, benefits, and challenges of waste minimisation in practice. Findings reveal a high level of material waste awareness and associated reduction strategies among professionals. However, attitudes and perceptions toward waste minimisation vary significantly with some professionals viewing waste reduction as essential, while others perceived construction waste as inevitable or difficult to minimise. Positive attitudes and perceptions when reinforced by supportive norms and enabling environment are critical for effective CE-aligned waste minimisation. The study contributes to theory by providing context-sensitive application of TPB to construction waste behaviour and extending CE research in developing country contexts. It offers actionable insights for policymakers, industry stakeholders, and professional bodies on embedding waste minimisation into design, procurement, and construction processes through capacity building, collaborative practices, and enabling policy and market conditions. In conclusion, the study advances understanding of the behavioural and perceptual factors influencing material waste minimisation and CE implementation.</p>