 This will be a randomized controlled trial of n345 Veterans with symptomatic knee OA in two VA Integrated Networks VISN 6 sites, with participants assigned to two study arms: STEP-KOA and Arthritis Education Control AE. STEP-KOA will begin with three months of access to a low-resource internet-based exercise training program that uses patient-specific information to determine and deliver an appropriate personalized exercise plan Step 1. Participants who do not meet response criteria for clinically meaningful improvement in pain and function after three months of Step 1 will additionally receive telephone calls from an exercise counselor for three months, to facilitate adherence and address barriers to physical activity Step 2. Participants who still fail to meet response criteria after Step 2 will receive in-person physical therapy visits, which address specific functional impairments and further tailor exercise recommendations Step 3. Outcomes will be assessed at baseline, 3-months, 6-months, and 9 months primary outcome time point. Veterans in the AE group will be offered participation in STEP-KOA after completing study assessments. The primary outcome will be the Western Ontario and McMasters Universities Osteoarthritis Index WOMAC, a measure of lower extremity pain, stiffness and function. The secondary outcomes will be objective measures of physical function. The main study analyses will compare the STEP-KOA intervention to the AE control condition at follow-up time points. The investigators will also evaluate patient characteristics associated with the need for progression to each Step and will conduct a cost-effectiveness analysis of STEP-KOA. This stepped exercise intervention is matched with patient needs, and it also provides the VA with a potential approach for focusing limited physical therapy resources toward patients who do not respond adequately to initial, less resource intensive and costly strategies to improve physical activity and related outcomes. 