Access to this document was granted through an Emerald subscription provided by emeraldsrm:198285 [] For AuthorsIf you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -In today's market, firms are riding on the wave of globalisation to enhance competitiveness through corporate collaboration in new product development (NPD). In joint NPD, huge amounts of information and knowledge are interchanged among business partners. However, industrial experience and past research have indicated that knowledge sharing among firms invite opportunism, that is, knowledge being leaked or misused by others. To determine the means to rectify the problems of opportunism in joint NPD, the purpose of this paper is to investigate the effect of commitment and knowledge sharing on opportunism. Design/methodology/approach -An online questionnaire survey was conducted to verify the research model with 312 valid responses from manufacturing firms. The survey data were analysed by structural equation modelling, and the findings were verified by follow-up interviews. Findings -Contradictory to most studies, this study finds that knowledge sharing among committed business partners suppresses, rather than invites, opportunism. Research limitations/implications -This finding is new in the literature with strong managerial implication. Firms that hesitate to share their knowledge with others because of the fear of opportunism should commit more seriously to their business partners so that they could share knowledge for better NPD. Originality/value -This study has reversed the sceptical belief of knowledge sharing leading to opportunism. This new belief will encourage corporate collaboration in joint NPD. However, for a comprehensive view on opportunism in inter-firm NPD, other governance mechanisms, that is, contract and trust, should also be studied in future research.