SilverCloud and THIS WAY UP (TWU) are two internet-delivered cognitive-behavioral therapy (iCBT) programs that have demonstrated effectiveness for anxiety and depression, yet little is known about their comparative effectiveness. This non-randomized program evaluation compared client satisfaction, subjective engagement, and treatment outcomes between the SilverCloud and TWU programs. Participants were 195 adult patients (106 using TWU and 89 using SilverCloud) enrolled in a digital CBT clinic who completed assessment measures at pre-treatment, mid-treatment, post-treatment, and one-, two-, three-, and four-month follow-ups. As hypothesized (preregistration: osf.io/x6bmy), patients in both programs reported high client satisfaction, and experienced improvements in depression (s = -0.79 and -0.78), anxiety (s = -0.95 and -0.84), and functional impairment (s = -0.42 and -0.45), from pre- to post-treatment that were maintained at four-month follow-up. However, according to exploratory analyses, the slope of change in treatment outcomes was not significantly different between programs during the treatment and follow-up phases. As hypothesized, patients who used SilverCloud self-reported significantly greater subjective engagement with their iCBT program compared to patients who used TWU (=0.36). However, contrary to hypotheses, client satisfaction was not significantly different between programs. This non-randomized program evaluation offers minimal evidence that one program was better than the other, though findings require replication in a randomized controlled trial and larger sample. Results provide further support for iCBT as a viable option to extend access to high-quality treatment for anxiety and depression.