As interest grows in mindfulness training as a psychosocial intervention, it is increasingly important to quantify this construct to facilitate empirical investigation. The goal of the present studies was to develop a brief self-report measure of mindfulness with items that cover the breadth of the construct and that are written in everyday language. The resulting 12-item measure demonstrated acceptable internal consistency and evidence of convergent and discriminant validity with concurrent measures of mindfulness, distress, well-being, emotion-regulation, and problem-solving approaches in three samples of university students. To address potential construct contamination in two items, data are also presented on an alternate 10-item version of the measure.