ObjectivesThere is evidence of a significant role for therapeutic alliance (TA) in psycho‐oncology care. This review aims to provide an overview by systematically identifying key characteristics of TA in this setting and exploring related concepts.MethodsPubMed, PsycInfo and Web of Science were systematically searched for empirical studies on adult cancer patients receiving psycho‐oncological care considering TA. Quality assessment was undertaken using the Mixed Methods Appraisal Tool. A narrative synthesis was conducted.ResultsOf the 4647 identified publications, 24 quantitative, qualitative and mixed‐methods studies were included. Characteristics of studies, interventions and samples were heterogenic. Patients consistently reported high TA scores. Favourable associations of TA with distress and well‐being and mixed results for further outcomes and compliance were detected. Associations between the patient's and therapist's characteristics yielded mixed results. Qualitative evidence pointed to a unique nature of TA in psycho‐oncology, for example, patients experiencing it in the context of other patient–provider relationships occurring in the context of the disease.ConclusionThe review displays a unique synopsis of a heterogenic, quickly developing research field. First hints towards the efficacy and particularity of TA in psycho‐oncology are delivered. Results encourage further focus on TA, both in psycho‐oncological research and in clinical practice.