Background: Anxiety disorders are a highly prevalent cause of impairment globally with generalized anxiety disorder (GAD) sharing many features with other anxiety disorders. Aims: The present study investigated the helpful and hindering events and impacts for individuals with generalized anxiety who engaged with a supported 6-week online intervention based on cognitive behavioural therapy (iCBT). Method: Participants (n = 36) completed the Helpful and Hindering Aspects of Therapy (HAT) for each session. A descriptive-interpretative framework was used to analyse the data. Results: Helpful events were identified by participants as CBT techniques including psychoeducation, monitoring, cognitive restructuring and relaxation, and found supporter interaction, mindfulness and reading personal stories helpful. The associated impacts were identified as support and validation; behavioural change/applying coping strategies; clarification, awareness, and insight; reassurance/relief; and self-efficacy/empowerment. Hindering events were identified as treatment content/form; and amount of work/technical issues, which led to impacts such as frustration/irritation; increased anxiety; and isolation. Conclusion: The implications of the results, potential future directions of research and limitations of the study are discussed.