Background: Although internet-delivered cognitive behaviour therapy (ICBT) yields large clinical outcomes when accompanied by therapeutic support, a portion of clients do not benefit from treatment. In ICBT, clients review treatment materials online typically on a weekly basis. A key component of therapist-assistance involves answering questions as clients review and work on assignments related to the treatment materials. Aims: The goal of this study was to enhance understanding of the nature of client questions posed during ICBT and examine potential associations between the number of questions asked and treatment outcomes in order to provide insight into how to improve ICBT for future users. Method: Content analysis was used to qualitatively analyse and identify questions that 80 clients asked their designated therapist over the course of an 8-week ICBT programme for anxiety and depression. Results: On average, clients sent six emails during the course of treatment, of which less than two questions were asked. Of the 137 questions posed by clients, 46.72% reflected questions designed to enhance understanding and apply the material and techniques reviewed in the programme. Additional questions were categorized as clarifying the therapeutic process (22.62%), addressing technical challenges (18.25%), and seeking assistance with problems outside the scope of ICBT (12.41%). Number of client questions asked was not significantly correlated with the number of lessons completed, symptom change, or perceptions of therapeutic alliance. Conclusions: Findings can inform future practitioners who deliver ICBT of what to expect with this treatment approach and also assist in the development of future ICBT programmes.