Although alternative methods have been proposed, mindfulness is predominantly measured by means of self-assessment instruments. Until now, several scales have been published and to some degree also psychometrically validated. The number of scales reflects the widespread research interest. While some authors have started to compare the underlying concepts and operationalizations of these scales, up to now no overview has been presented describing, contrasting, and evaluating the different methodological approaches towards measuring mindfulness including questionnaires and alternative approaches. In light of this, the present article summarizes the state of mindfulness measurement. Recommendations on how current measurement practice may be improved are provided, as well as recommendations as to what measurement instruments are deemed to be most appropriate for a particular research context.