The primary aim of this study was to examine the underlying relationship between adult attachment, dispositional mindfulness, and emotion regulation, and investigate how well these constructs can predict coping and well-being. A university sample of participants (n = 174) completed an online survey to assess attachment (anxiety, avoidance, disorganized), emotion regulation, dispositional mindfulness, coping behaviors, and psychological well-being. Exploratory factor analysis assessed the underlying relationship between measures of attachment, emotion regulation, and mindfulness, and presented a two-factor solution accounting for 47% of total variance across participant scores. Attachment, mindfulness, and emotion regulation subscales differentially loaded across the two factors. The first factor, “resilient mental functioning,” accounted for 33% of variance; the second factor, “disorganized emotional functioning,” accounted for 14% of total variance. These two extracted factors were used in subsequent mediation modeling to determine the effects of coping behaviors on the relationship between the extracted factors and six subscales of psychological well-being. Mediation analyses revealed that defeatism coping was a significant mediator in the relationship between resilient mental functioning and five of the psychological well-being scales and between disorganized emotional functioning and all six of these scales. The results add to the current understanding of the relationship between all three constructs and are the first to examine the construct of adult disorganized attachment and its possible role in the relationship between adult attachment and dispositional mindfulness, as well as its influence on emotion regulation.