Objective: To describe the development of a new measure, the TICOMETER, a brief assessment tool that can measure trauma-informed care (TIC) in health and human service organizations at a single point in time or repeatedly as well as determine training needs. Methods: With the input of an expert panel we selected relevant items and domains. Initially we organized the instrument into 5 domains consisting of 189 items that were then scored by 424 service providers representing 68 organizations. Using an iterative approach, we selected the 35 psychometrically strongest items across 5 domains. Within each domain a set of rating scale models (RSM), confirmatory factor analytic models (CFA), internal consistency and test–retest reliability statistics, and receiver operating curves were used to assesse the item fit, reliability, and face and construct validity of the TICOMETER. Results: The 5 TICOMETER domains had high reliability along with good item and CFA fit. Strong associations between domain scores and a priori rankings demonstrated validity of the domains. Conclusion: The TICOMETER has strong psychometric properties, creating new possibilities for assessing the level of TIC offered by an organization, monitoring progress in service delivery over time, determining training needs, and developing trauma-informed policies. (PsycINFO Database Record (c) 2017 APA, all rights reserved)