One hundred sixty-four patients with moderate to severe symptomatic medial knee osteoarthritis were randomized to receive flat flexible shoes (n=82) or stable supportive shoes (n=82) for at least six hours daily over six months. The primary outcomes were changes in walking pain (measured on an 11-point numerical rating scale) and physical function (assessed by the Western Ontario and McMaster Universities Osteoarthritis Index). Secondary outcomes included additional pain measures, physical activity, and quality of life. At six months, 161 participants (98%) completed primary outcome assessments. The results showed that stable supportive shoes led to significantly greater reductions in walking pain than flat flexible shoes (mean difference, 1.1 units; 95% CI, 0.5 to 1.8; P=0.001), but there was no significant difference in function improvement between groups (mean difference, 2.3 units; 95% CI, −0.9 to 5.5; P=0.167). Quality of life and ipsilateral hip pain also favored stable supportive shoes. More adverse events were reported with flat flexible shoes. These findings suggest that stable supportive shoes may be a more effective self-management strategy for knee osteoarthritis-related pain.