--- - |2 Trait mindfulness and mindfulness in the context of romantic relationships may not be completely overlapping constructs. This study adapted an existing measure of trait mindfulness to assess the tendency to be mindful in romantic relationships, the Relationship Mindfulness Measure (RMM). Using data from 185 young adults, the results supported the RMM's internal consistency, test–retest reliability, and concurrent and predictive validity. The RMM accounted for a significant portion of variance in positive relationship quality, negative relationship quality, and anxious and avoidant attachment, even after controlling for trait mindfulness. Based on these findings, assessing relationship mindfulness may improve research exploring the role of mindfulness in romantic relations and therefore facilitate the development and refinement of mindfulness training programs for couples. - Journal of Marital and Family Therapy, Volume 44, Issue 4, Page 575-589, October 2018.