Awareness and un-clinging have been emphasised in Buddhist discourse as important facets of mindfulness practice for over 2500 years. However, there is a lack of rigorous research examining the relationship between these two elements and their importance to well-being. To evaluate these abstract constructs, the current study adopted multiple assessment modalities; namely, a self-report scale, experience sampling (assessing 'momentary mindfulness'), and semi-structured interviews (assessing 'rater-rated mindfulness'). A total of 415 participants completed the questionnaire survey. Among them, 71 participants further took part in the experience sampling procedure and semi-structured interviews. The findings reveal that self-reported awareness was mildly correlated with momentary mindfulness (r = .35) but was not significantly correlated with raterrated mindfulness. Self-reported un-clinging was moderately correlated with raterrated mindfulness (r = .53) but was not significantly correlated with momentary mindfulness. Un-clinging, but not awareness, can distinguish meditators from non-meditators. Lastly, based on the Buddha's mindfulness discourse, a path analysis model illustrates that the effects of un-clinging and awareness on stress reduction are mediated by emotional intelligence and non-attachment. Practical implications and future research designs are discussed. Despite the widespread applications of mindfulness-based interventions, to date, there is no consensus regarding the defining criteria of mindfulness (Mooneyham et al. 2016). Researchers have debated whether mindfulness should be conceptualised as purely the manifestation of consciousness or as a multifaceted construct involving different attitudes and skills, such as awareness,