Resistance can be a substantive problem that limits treatment efficacy in cognitive behavioral therapy (CBT). Resistance often arises in a context of client ambivalence about change and has been consistently found to be exacerbated by directive responses and reduced by supportive ones. When not properly managed, resistance can have detrimental consequences for the therapeutic alliance and both proximal (e.g., engagement, homework compliance) and distal (e.g., symptom severity) treatment outcomes. Given its impact, resistance should be considered a key process marker in CBT. Motivational interviewing (MI) provides strategies for ‘rolling with resistance’ and there is mounting evidence that it can be successfully integrated with CBT to improve overall treatment response. This paper will review the research on resistance and ambivalence, particularly research conducted in the context of CBT. MI and its ability to successfully address these impasses will be outlined in detail, together with a clinical illustration.