Evidence-based diagnosis specific cognitive behaviour therapy (CBT) protocols for anxiety disorders, currently recommended in national clinical guidelines, have shortcomings in relation to the application of group therapy in the mental health service. Transdiagnostic CBT is theory-driven, targeting common personality traits and emotion-driven behaviour observed in all of the anxiety disorders. This review recapitulates the theory and the evidence base. More head-to-head comparison studies are needed, in particular concerning group therapy. The current evidence is, however, very promising.