Resilience comprises various neurobiological, developmental, and psychosocial components. However, existing measures lack certain critical components, while having limited utility in low-to-middle-income settings. We aimed to develop a reliable and valid measure of resilience encompassing a broad range of components and that can be used across different income settings. We also set out to develop empirical cutoff scores for low, moderate, and high resilience. Results from 686 participants revealed the emergence of three components: positive affect ([alpha] = 0.879), early-life stability ([alpha] = 0.879), and stress mastery ([alpha] = 0.683). Convergent and incremental validity was confirmed using an existing resilience measure as the benchmark. Concurrent validity was also confirmed with significant negative correlations with measures of depression, anxiety, posttraumatic stress disorder, and sleep disruption. Finally, we successfully determined cutoff scores for low, moderate, and high resilience. Results confirm that the Resilience Index is a reliable and valid measure that can be utilized in both high- and low-to-middle-income settings.