The present research proposes that dispositional mindfulness may play a key role in our understanding of romantic jealousy, conceptualized as a multidimensional construct consisting of three components: cognitive, emotional, and behavioral. All three components involve experiencing an outside threat, but diverse aspects of the experience are implied: cognitive jealousy entails thoughts and suspicions, emotional jealousy entails affective responses, and behavioral jealousy entails surveillance behaviors. Across five studies ( N = 3275), using non-dyadic and dyadic data, different measurement scales for mindfulness, and different indicators of relationship functioning (couple satisfaction, relationship quality, occurrence of conflicts), we consistently found that mindfulness is negatively related to cognitive and behavioral jealousy. This is explained by increased self-esteem characterizing mindful individuals. In turn, decreased cognitive and behavioral jealousy resulted positively related to couple satisfaction and relationship quality, whereas negatively to occurrence of conflicts. We did not find significant relations between mindfulness, self-esteem, emotional jealousy, and relationship functioning. These results provided evidence, which was also confirmed by a mini meta-analysis, that mindfulness may constitute a protective factor against detrimental cognitive and behavioral (vs. emotional) romantic jealousy. We discuss how these results advance literature and open new research avenues for both theoretical and applied purposes.