This study examined whether social support and invalidation (lack of understanding and discounting by others) are differently associated with physical and mental health. Participants were 1455 patients with fibromyalgia, rheumatoid arthritis, ankylosing spondylitis, osteorarthritis, or another rheumatic disease. Participants completed online questionnaires. Social support correlated negatively with discounting responses of others (moderately) and lack of understanding (strongly). Both invalidation and social support were additively associated with patients' mental health, but only discounting was significantly associated with patients' physical health. This suggests that improving health of patients with rheumatic diseases requires the consideration of both social support and invalidation.