The Kentucky Inventory of Mindfulness Skills (KIMS) is a 39-item self-report measure based on a conceptualization of mindfulness as a set of skills that can be taught and practiced. It was influenced by understandings of mindfulness skills in dialectical behavior therapy, mindfulness-based cognitive therapy, and mindfulness-based stress reduction. The KIMS has four subscales: observing,describing,acting with awareness, and accepting without judgment. Content validity of the items was supported through ratings by experts. The four subscales have been shown to have adequate to good internal consistency and test-retest reliability, to be correlated in the expected directions with a variety of constructs, and to change significantly with mindfulness training. A four-factor structure has been supported in clinical and nonclinical populations. A hierarchical factor structure in which the four factors are elements of an overarching mindfulness construct has not been supported, probably because of characteristics of the observing scale; this issue has been explored using the Five Facet Mindfulness Questionnaire, a closely related instrument. The KIMS has been shown to have acceptable psychometric properties in French and German translations.