Anxiety is a major contributor to poor quality mental health for many people in our community, and is a leading cause of presentations at medical and health clinics. Patterns of trait anxiety, or dysfunctional responding, have become ingrained in individuals’ approaches to problems they face. Research has shown that psychological wellbeing and interpersonal attachment style are both predictors of trait anxiety. However, the relationships among these variables have not been clarified. The current study sought to determine whether psychological wellbeing mediates the relationship between interpersonal attachment style and trait anxiety, and which of the six psychological wellbeing subscales would contribute most to any mediation effects. A convenience sample of 149 adult participants from South East Queensland, Australia completed a series of online questionnaires including a demographic questionnaire, the Trait Anxiety subscale of the State-Trait Anxiety Inventory (STAI-Form Y2), the Inventory of Parent and Peer Attachment (IPPA), Ryff’s Psychological Wellbeing Scale (PWB), and a Social Desirability Scale (SDS-17). Psychological Wellbeing was found to partially mediate the relationship between interpersonal attachment style and trait anxiety. The Positive Relations with Others subscale of the PWB was the only significant sub-scale of the PWB that significantly predicted trait anxiety. Overcoming anxiety appears to be most related in our sample to those who deal better with interpersonal relations. Targeting this aspect in treatment approaches appears most likely to lead to improved outcomes for clients.