Background: Physical activity (PA) research in multiple sclerosis (MS) typically has not focused on persons newly diagnosed with the disease. This is noteworthy as PA might be most amenable for change in the early stages of MS and further yield long-term benefits over the disease course.

Objective: This study examined correlates of PA based on the Capability-Opportunity-Motivation-Behavior (COM-B) model in persons newly diagnosed with MS.

Methods: Participants newly diagnosed with MS (i.e., ≤ 2 years; n = 152) completed an online Qualtrics survey that assessed PA levels and COM-B constructs. Multivariate Analysis of Variance and Discriminant Function Analysis identified the constructs that differentiated PA groups.

Results: The results indicated that 39.5% and 34.2% of the sample were classified as Insufficiently Active and Not Regularly Active, respectively. The results further identified Intention, Action Control, Action Self-efficacy, Action Planning, Outcome Expectation, Goal Setting, and Recovery Self-efficacy, and Fatigue as the primary correlates of PA in persons newly diagnosed with MS.

Conclusions: Our results identified COM-B constructs in the Capability and Motivation domains as the primary correlates of physical activity in persons newly diagnosed with MS. Such research might inform interventions for changing physical activity in this MS subpopulation.