Purpose– This study aims to develop a standardized instrument to measure open innovation and trust. The instrument is designed to examine the willingness of those involved in supply chains (SCs) to apply open innovation. It may also be used to observe the potential role of customers, competitors and suppliers in improving the performance of SCs.Design/methodology/approach– This survey of the extant studies of Multinational Automobiles Assembly lines in Egypt involved a questionnaire, which was provided across all grades at the middle managerial level. This questionnaire was divided into two main sections. The first section was concerned with elements of open innovation such as innovation, shared values and shared knowledge. The second section was focused on interrelated types of organizational and extra-organizational trust.Findings– The developed instrument was designed to access and analyze the different types of trust required for the optimal application of open innovation. Its purpose was to enhance customer satisfaction, and to help to create better internal-customer performance and the provision of innovative products. This explorative study indicated that Multinational Automobile Assembly lines in Egypt are willing to apply open innovation methods to improve their performance.Research limitations/implications– The study had a number of limitations. As the survey was conducted entirely on Multinational Automobile Assembly lines in Egypt, the applicability of the proposed scale will need to be tested further on different countries and types of industry.Originality/value– There is little empirical research about implementation of open innovation. Practitioners and researchers should find value in this unique instrument tool.