Theoretical understanding of generalised anxiety disorder (GAD) suggests that individuals with GAD are fearful and avoidant of internal experiences, including cognitions, emotions, imagery and somatic arousal. Metacognitive awareness (MA) is defined as the extent to which thoughts and feelings are experienced as mental events, rather than direct reflections of truth. From findings that depressed patients showed deficits in MA (Teasdale et al., 2002), it was hypothesised that individuals with GAD experience similar deficits. Results found lower MA in 32 individuals with GAD compared with 32 controls, which was associated with poorer coping abilities, greater trait worry, stronger fear of emotions and more maladaptive beliefs about worrying. MA also mediated the relationships between emotional distress and coping ability and between emotional arousal and trait worry. Randomised treatment with cognitive behavioural therapy (CBT; n ¼ 8) or mindfulness-based therapy (MBT; n ¼ 10) showed MBT produced faster outcomes in reducing diagnostic severity and depression levels compared with CBT at post-treatment, although there were no treatment differences at 6-month follow-up. Both treatments also showed comparable increases in MA at 6-month follow-up. The current research extends the theoretical understanding of GAD and implicates the targeting of MA deficits in the treatment of GAD.