The present study examined the pattern of associations among physical activity, social support, mobility disability, perceived stress, and depressive symptoms in relapsing-remitting MS (RRMS). Persons (N = 218) with RRMS completed a battery of questionnaires that was sent and returned through the United States Postal Service (USPS). Bivariate correlation analysis indicated that physical activity and social support were both inversely associated with depressive symptoms (r's = -0.288 and -0.386, p ≤ 0.05, respectively). Multiple linear regression analysis indicated that physical activity (β = -0.21, p = 0.002) and social support (β = -0.37, p = 0.0001) were independently associated with depressive symptoms. Path analysis confirmed that the associations between physical activity and social support with depressive symptoms were indirect via mobility disability and perceived stress. Collectively, the evidence indicates that physical activity and social support are independently and indirectly associated with depression via mobility disability and perceived stress in relapsing-remitting MS. This supports the design of interventions and programs that target physical activity and social support for reducing depressive symptoms among persons with MS.