The Toronto Mindfulness Scale-Trait Version (Trait TMS) is a 13-item, 2-factor self-report measure of individual differences in dispositional mindfulness, adapted from the previously validated state version of the TMS. The TMS developers conceptualized mindfulness as having two components: (1) an intentional self-regulation of attention toward present experience and (2) a curious, accepting, and open orientation toward present experience as it arises. Based upon this metacognitive framework, the Trait TMS, like the state version of the TMS, measures two factors of mindfulness: Decentering reflects an awareness of one’s experience with some distance and disidentification rather than over-identifying with thoughts and feelings, and Curiosity reflects an attitude of wanting to learn more about one’s experiences. Evaluations of the substantive validity of the Trait TMS subscales, Decentering and Curiosity, have demonstrated good internal consistency as well as good, albeit limited, convergent and discriminant validity with other validated mindfulness measures. The initial development of the Trait TMS did not examine structural validity or test-retest reliability. No studies beyond the initial validation study of the state version of the TMS have independently examined the psychometric properties of the English language Trait TMS factors; however, the Trait TMS has been validated in traditional Chinese.