Increasing evidence reveals the damaging impact of having one's chronic pain symptoms invalidated through disbelief, discrediting, and critical judgement. In other instances, a caregiver's over-attentiveness to the daily tasks of individuals with pain can be problematic, potentially undermining rehabilitation. The aim of this study was to develop an instrument to measure different aspects of invalidation perceived by people with chronic pain. Item generation was informed through literature review and a thematic analysis of narratives from 431 peer-reviewed articles. The crowdsourcing platform Prolific was used to distribute survey items to participants. In Study 1A, Principal Component Analysis was performed on data from 302 respondents, giving rise to 4 subscales, including: Invalidation by the Self, Invalidation by Immediate Others, Invalidation by Healthcare Professionals, and Invalidation by Over-attentive Others. Confirmatory Factor Analysis of data collected from aonther 308 individuals in Study 1B supported the 4-factor model of the Pain-Invalidation Scale (Pain-IS) and identified a best-fit model with 24 items. The Pain-IS was further validated in another 300 individuals in Study 2. The Pain-IS demonstrates sound psychometric properties and may serve as a valuable tool for use by clinicians in the detection of pain-invalidation issues, as a first step in patient pain management. Perspective. Links between pain-invalidation and pain levels, as well as functional detriment, highlight the importance of having one's chronic pain experience heard, believed and accepted. The Pain-Invalidation Scale is designed to identify domains where invalidation of the patient's pain should be addressed to promote emotional processing, treatment adherence and improved outcomes.