Patients differ in their response to treatments. There is obvious clinical utility in establishing patient characteristics that are associated with differential treatment responses (i.e., are effect modifiers or moderators of treatment response). Factors that moderate response to cognitive behavioural therapy (CBT) remain unclear. This study investigates whether factors prognostic of general depression outcome generally are also moderators of response to online CBT in a sample of depressed patients recruited through U.K. general practices.