The aim of the paper is to identify and systemise dimensions and measures that can be used to evaluate buyer-supplier relational capital (RC). The authors used a literature review methodology composed of the following phases: question formulation, keyword search in databases, screening and analysis of articles. As a result, 44 articles were selected and finally analysed in detail. It was found that several theories can help to explain how buyer-supplier relationships contribute to a company’s value and competitive advantage. Furthermore, RC as an element of social capital deserves more investigation in a supply chain management context. Accordingly, to date there has been no relevant in-depth studies exploring the measurement of relational capital in supply chains. On the base of the review of research articles published between 2004 and 2018, the list of items used by researchers to measure the relational capital was explored. Then, authors proposed a construct for relational capital consisting of 5 items such as: trust, close interaction, respect, reciprocity and commitment, that were shortly discussed. Taking them all into account, an authorial definition of supply chain relational capital was proposed. Although, the final results contribute to the study of RC measurement within buyer-supplier relationships in supply chains, the analysis still has some shortcomings that need to be addressed in further literature studies and empirical research.