The increased demand for and proliferation of mindfulness-based interventions (MBIs) within clinical treatment programs underscores the need for MBI clinicians to better understand the Buddhist psychological and theoretical underpinnings of such treatments. Of particular importance is familiarity with the stages of insight, the predictable developmental sequence of the Theravada Buddhist practices from which MBIs derive their core curricular components. This paper outlines the primary reasons why MBI clinicians need to be aware of the stages of insight, including: (1) some MBI participants appear to progress through the initial stages of insight, even during a relatively short period of time, such as an 8-week program; (2) knowledgeable clinicians may be better able to recognize the stages of insight and adjust practice instructions to facilitate participants’ navigation of these stages; (3) clinically significant symptoms that may be encountered during progress through the stages of insight need to be recognized by clinicians and appropriately addressed. Modifications to standards for clinician competency are suggested, and areas for future clinical and neurobiological research related to the stages of insight are explored. The risks and ethical issues associated with delivering MBIs in a health care setting, and informed consent regarding potential progress along the stages of insight, are discussed.