Background: Panic disorder (PD) has a chronic nature, especially as a result of maladaptive coping strategies to deal with stressful events. Aims: To evaluate the impact of booster sessions with cognitive techniques on coping strategies, resilience, and quality of life (QoL) in patients previously submitted to standard cognitive-behavioural group therapy (CBGT) for PD. Method: A controlled clinical trial with 44 patients with PD (intervention = 20; control = 24) who had previously completed a 12-week CBGT protocol. PD, anxiety, and depression severity symptoms were assessed at baseline and 1, 6, and 12 months after the booster sessions. Coping strategies, resilience, and QoL were assessed by Coping Strategies Inventory (CSI), Resilience Scale, and WHOQOL-BREF respectively. Results: Over time, a significant improvement in PD and depression symptoms was observed in both groups. A significant increase in the QoL social relations domain was found in the booster group, considering a time/group interaction. Coping and other QoL domains did not change after the booster sessions. Changes in resilience were dependent on the intensity of symptoms, with negative but non-significant correlations. Conclusions: The improvement in PD and depression symptoms for both groups may be a result of the group format of the intervention. Group booster sessions after CBGT are useful to maintain the benefits obtained with CBGT.