In most effectiveness studies on lumbar supports for patients with low back pain, insufficient data are reported about adherence. In a secondary preventive RCT, we found beneficial effects and a good adherence among home care workers with low back pain. To target the use of lumbar supports on those patients who can benefit optimally from usage, we need to know why people are adherent. We used the attitude, social support and self-efficacy model to identify determinants for prolonged adherence to wearing a lumbar support. The strongest predictor for intending sustained use of a lumbar support was a positive attitude towards lumbar supports, explaining 41% of the variance (B = 1.31; p < 0.001). Social support and self-efficacy played a minor role. The intention for prolonged use of a lumbar support for workers with recurrent back pain was mainly explained by a positive attitude. The discomfort of a lumbar support was outweighed by perceived benefit.