Self-transcendence is thought to increase well-being and is implicitly promoted in contextual cognitive behavioral therapies (CCBTs). This study conceptualizes, develops, and validates the first comprehensive CCBT-informed self-transcendence questionnaire. Using a CCBT-informed theory, we propose four self-transcendence facets: distancing oneself from mental content, distinguishing an observer of mental experience that is separate from the content of experience, experiencing innate connectedness with other beings, and noticing the constantly changing nature of experience. We measured these facets with items from existing relevant questionnaires and novel, expert-informed items. Exploratory factor analyses and bifactor exploratory structural equation models supported the first three of these facets. Those factors evidenced convergent validity with decentering, defusion, experiential avoidance, and mindfulness, and criterion and incremental validity in predicting psychological well-being. Our findings support a CCBT-informed model of self-transcendence, introduce the first instrument to comprehensively measure the self-transcendence facets we identified, indicate links with well-being, and suggest future intervention targets.