Purpose Construction framework agreements are identified by the UK Government’s Construction Strategy 2025 as an integrated procurement path to improve construction industry efficiency. However, criticisms from the industry have arisen from the lack of transparency and incorrect application of such frameworks. This paper aims to examine the client and supplier relationships within a framework agreement to discover what behaviour change drivers should be applied in the framework process to achieve the desired project outcomes. Design/methodology/approach A triangulation approach was adopted. An initial literature review on organisational behaviour and job performance theories was conducted followed by a qualitative expert review survey of client construction managers to confirm the project outcomes desired by public-sector clients and the associated behaviour change drivers. This was followed by a qualitative multiple-case study investigation of eight typical framework projects to form a commonality of views to explain the impact of behaviour change drivers on project outcomes. Findings Results from both qualitative studies demonstrated that improvements in project outcomes of time, cost, quality, sustainability and closer relationships can be driven by two sets of behaviour drivers: client organisational behaviour change drivers (setting up incentive and risk-sharing procurement approach, effective communication through development of stronger relationships and performance monitoring using contract key performance indicators) and supplier contextual behaviour change drivers (motivating conscientious behaviour and attitude towards self-improvement and innovations, supporting shared culture of providing services aligning with the client needs, promoting learning and development amongst all suppliers and most importantly providing trust and collaboration to the client). Research limitations/implications The investigation was based on an expert review with eight multiple-case studies conducted within the geographical area of England. Further research should be conducted nationwide so that the findings can become more robust and benefit the entire public sector. Practical implications It is suggested that framework managers should apply the supplier contextual performance drivers as selection criteria in the procurement process, whilst the client organisational performance drivers should be applied in the whole procurement and construction monitoring process to drive project outcomes aligned with the government construction policy objectives. Originality/value This research demonstrates that the project behaviour of clients and suppliers can be shifted within the construction framework environment to yield the desired project outcomes. This can be achieved by applying the client organisational behaviour drivers and the supplier contextual behaviour change drivers in tandem to optimise the framework process.