Meditative insight is conceptualised as being at the core of change mechanisms in meditation and mindfulness. Although this construct is fundamental in traditional meditation theories, it has not yet received attention in scientific work. Drawing on traditional Buddhist formulations of meditation, this study outlines the development and psychometric analysis of a new instrument to assess meditative insight. Self-report data on positive and negative psychological functioning indicators were collected from a large (N = 881) heterogeneous cross-section of meditation practitioners. The findings support the reliability and validity of the new instrument and confirm that (1) meditative insight varies as a function of amount and type of meditation training, (2) mindfulness and insight are overlapping yet distinct constructs, (3) insight predicts psychological health and functioning, and (4) insight mediates the effect of mindfulness on psychological health.