Social commerce (s-commerce) has gained its popularity among users of social media sites as an online shopping platform including Instagram. Since its introduction in 2010, Instagram has become a chosen S-Commerce platform due to its easy to use features, its image attractiveness and its non-distracting interface. However, trust remains as the main issue in Instagram since Instagram involves mostly Consumer-to-Consumer (C2C) and transactions are made through private accounts. This study proposes an instrument to evaluate the trustworthiness of Instagram sellers and validates the items using statistical techniques. A questionnaire was designed and distributed as the instrument. Data was collected and analysed using SPSS to test on the item’s reliability. 41 responses were collected for the pilot study, and the finding shows that the instrument is a valid and reliable measurement for the research model development.