Purpose - This study aims to examine the antecedents of relationship learning in partnerships and develop a research model that explains relationship learning through three complementary constructs: relational practices, social capital and suppliers' relationship-specific investments. Design/methodology/approach - The study examines data drawn from interviews regarding 195 customer-supplier relationships from the metal and electronics industries. In terms of methodology, the study employs structural equation modelling. Findings - The findings indicate that relational practices, social capital and supplier's relationship-specific investments explain relationship learning to a great extent. Research limitations/implications - The present study has some limitations, such as the use of cross-sectional data and a limited sample size. More empirical research is needed on the antecedents and mechanisms of relationship learning as well as the interactions among antecedents. Practical implications - The results suggest that companies must be able to facilitate the development of relational practices, social capital and suppliers' relationship-specific investments, as these constructs explain relationship learning largely. Originality/value - The prior literature lacks empirical evidence on the antecedents of relationship learning, particularly in the context of partnerships. The present study demonstrates a significant impact of three antecedent constructs on relationship learning.