ABSTRACT Objectives: Awareness is a key component of concepts related to well-being, such as mindfulness and authenticity. Similarly, interventions to enhance mindfulness and well-being often focus on developing awareness. But measuring the effect of awareness development represents a challenge due to the lack of reliable and valid measures focused specifically on awareness outcomes. This study aimed to develop and validate the Awareness Outcomes Measure (AOM) using modern Rasch methodology. Method: The measure was developed from Self-Awareness Outcomes Questionnaire (SAOQ) items, drawn from previous research with awareness-development experts. A partial credit Rasch model was applied to examine the psychometric properties of the AOM with a combined sample of 713 participants from three English-speaking countries. Results: The 21-item AOM met expectations of the unidimensional Rasch model. It is a reliable and psychometrically sound instrument, invariant across sex, country, and age, designed to measure the outcomes of awareness development. Person-item thresholds demonstrated excellent coverage of awareness outcomes, and we developed an algorithm for ordinal-to-interval transformations presented in a table to further enhance precision of the AOM. Conclusions: In this study, we have developed and validated the AOM, providing researchers and practitioners with a robust measure of awareness outcomes that is suitable for use in a range of populations.