Background: Adults and children with cancer are referred to palliative care infrequently or late. Oncologists often gatekeep these referrals. Social exchange theory is used to explain physician referral behaviour in various clinical settings. Its utility in a cancer palliative care setting is not known. Methods: We used Karl Popper’s hypothetico-deductive approach to test the hypothesis. The hypothesis was that social exchange theory is a helpful framework for explaining oncologists’ palliative care referral behaviour in a cancer setting. The utility of the theoretical framework was tested against the empiric findings of a systematic review and original research. Results: Most components of social exchange theory known to explain physician referral behaviour like beliefs about the provider or service, emotions triggered during the professional engagement, its symbolism and stigma, the complexity of the referral task, efforts needed to achieve it, its cost, benefit, and value were similar in a cancer setting. Empirical findings suggest that oncologists provided strategies and solutions to better palliative care integration instead of comparing their existing engagement with potential alternatives and choosing them. Conclusion: Social exchange theory was found to be helpful in explaining oncologists’ palliative care referral behaviour. To further develop the social exchange theory based on the data used to test it, it is recommended to include feedback and solutions as a component of the theoretical framework alongside a comparison level for alternatives.