PurposeThe increasing adoption of digital technologies such as social media have changed the way consumers share knowledge about products and services among each other. The aim of this paper is to test what factors drive customers to share knowledge about products and services on social media pages.Design/methodology/approachA quantitative survey design was employed for this study. Empirical data were drawn from 358 consumers in Italy, using a purposive sampling technique. The hypothesised relationships were tested using ordinary least squares regression modelling.FindingsThe results of this study reveal that the usage frequency of online reviews (UFORs), social bonds (SBs), subjective happiness (SH) and reciprocity positively impact on customer knowledge sharing (CKS). By contrast, the perceived usefulness of online reviews (PUORs), helping others, customer susceptibility to interpersonal influence (CSII) and informational (INFO) do not impact CKS.Originality/valueTo the best of the authors' knowledge, this study is amongst the first to empirically test the antecedents of knowledge-sharing behaviours about products and services on online social media. The present work offers relevant implications for theory. First, the work enriches the customer knowledge management (CKM) theory by providing empirical evidence on factors leading to the higher sharing of knowledge amongst customers. Second, the work adds to the literature on social media, demonstrating the individual determinants on knowledge-sharing behaviours about products and services in online communities. Practically speaking, this paper identifies some key elements driving CKS in social media conversations. Thus, building upon the findings of this study, the authors provide some guidelines for social media managers and retailers for promoting CKS on social media pages.