Exercise is a time- and cost-efficient alternative to other evidence-based treatments for anxiety (e.g., psychotherapy, pharmaceutical) that also is associated with physical health benefits. Exercise protocols such as resistance training (RT) are efficacious at reducing symptoms of anxiety-related disorders (ARDs); however, there are challenges associated with effectively implementing such protocols, most notably, that people with ARDs may avoid physical activity, including exercise. Emerging research suggests that people with ARDs experience exercise-specific anxiety (e.g., exercise-related worries, fear of physical sensations associated with exercise) and identify this exercise anxiety as a major contributor to their exercise avoidance. Consequently, exercise interventions for people with ARDs may need to target exercise anxiety to support long-term exercise engagement. Evidence-based cognitive-behavioural techniques (CBT), such as cognitive restructuring, and exposure, can alter maladaptive thinking and behavioural patterns associated with anxiety. Teaching people with ARDs how to apply CBT techniques to exercise anxiety could help increase and support their exercise behaviour; however, research has not been conducted to test this hypothesis. The primary purpose of this proposed randomized controlled trial (RCT) is to examine whether adding a form of CBT (i.e., the Unified Protocol) to a program for people with ARDs is associated with superior exercise engagement as compared to groups that do not receive this intervention. This proposed RCT will also evaluate potential predictors of exercise frequency for people with ARDs, such as exercise knowledge, exercise self-efficacy, and exercise motivation. A total of 90 physically inactive participants with ARDs will be randomized into a month of one of the following conditions: Unified Protocol + RT, RT, or waitlist (WL). All participants (except WL) will receive and follow a comprehensive instructional exercise program, consisting of three weekly full body RT workouts. Participants in both RT groups will also receive the guidance of a personal trainer during their first month of following this program. Participants in both RT groups will complete three exercise sessions each week for 4 weeks and these sessions will be composed of personal trainer and independent exercise. Participants in the Unified Protocol +RT condition will also receive four weekly individual CBT sessions designed to support adherence to the exercise sessions. Exercise frequency will be measured using the number of recorded exercise sessions (at least 30 minutes in length) and physical activity will be measured using the International Physical Activity Questionnaire-Short Form. Presence and severity of ARDs will be assessed using the Structured Clinical Administered Interview for the Diagnostic Statistical Manual of Mental Disorders-5 (SCID-5) as well as disorder-specific self-report measures. Exercise anxiety will also be measured using a questionnaire designed for this study. Exercise frequency, anxiety disorder-specific severity, and exercise anxiety will be measured at baseline, weekly during the first month of exercise, and at follow-up at 1-week, 1-month, and 3-months. Diagnostic status will be evaluated at baseline and at 1-week follow-up. Exercise knowledge, exercise self-efficacy, exercise motivation, and physical activity, will be measured at baseline, 1-week-, 1-month-, and 3-month follow-ups. Multilevel modelling will compare exercise frequency and anxiety symptoms, across groups, at each time point. This RCT will be the first to evaluate whether the Unified Protocol can support people with ARDs to increase their exercise engagement. If the Unified Protocol does increase engagement, the Unified Protocol could be used by researchers and clinicians alike to support individuals with ARDs interested in using exercise to manage their anxiety, but who are experiencing difficulty maintaining an exercise regime.