Trust is crucial for achieving optimum benefits from supply chain integration and collaboration in the construction sector. Yet relationships between main contractors and subcontractors continue to be influenced by issues that promote vicious circles of distrust. This research investigates the trust influencing factors in main contractor–subcontractor relationships on projects. Empirical data was gathered from across four case studies through semi-structured interviews, non-participant observations and document reviews, and analysed using thematic analysis. Findings revealed that the change management process, economic climate, payment practices, perceptions of future work opportunities, job performance and the project-specific context influence trustfulness and trustworthiness of the different parties. The findings also imply that stronger trust in the main contractor's supply chain can only be realised and sustained through promotion of trustworthiness-induced rather than benefit-induced trustfulness.