I am developing and validating two behavioral assessments of nonjudgmental orientation to experience, a key dimension of mindfulness. Currently, mindfulness is most commonly assessed by self-report questionnaires, which suffer from numerous limitations. Developing measures beyond self-report to assess nonjudgment is essential to exploring its role in mindfulness-based interventions (MBIs) and contemplative practices. Additionally, the development of objective measures may prove useful for future neuroimaging and physiological research on nonjudgmental orientation to experience. We will develop two measures: (1) the Phenomenological Nonjudgment Writing Task (PNWT), a writing task coded for nonjudgmental qualities of thinking, and (2) the Nonjudgment Implicit Association Task (NIAT), a version of the well-validated Implicit Association Task adapted to assess the strength of associations between judgments and emotions. To validate the sensitivity of these measures to change and thus their suitability for research into the mechanisms of change for MBIs, a subset of the sample will also be randomly assigned to a nonjudgment or judgment induction, followed by an additional administration of the assessments. Validation of these measures would provide essential tools for further scientific inquiry into the role of nonjudgment in mindfulness and contemplative practices, as well for the development and evaluation of increasingly effective MBIs.