Foot orthoses and night splints have been used separately to treat patients with plantar fasciitis, but were not always successful. Combined use of both orthoses might give better outcomes. This study evaluated the effectiveness of a soft and self-adjustable dorsiflexion night splint in combination with an accommodative foot orthosis for patients with plantar fasciitis. Twenty-eight patients were assigned to group A (foot orthosis only) and group B (combination of foot orthosis and dorsiflexion night splints). A foot function index (FFI) questionnaire was used to evaluate the pain and functions of feet just before, 2 weeks after, and 8 weeks after the treatments. Results showed that subjects in group B had significantly reduced pain scores at week 2 (p < 0.001) and week 8 (p < 0.001). In group A, no statistical differences were noted in the pain (p = 0.15), disability (p = 0.56), activity limitation (p = 0.75), and total FFI (p = 0.35) scores for the three time periods. The application of foot orthoses with adjustable dorsiflexion night splints was found to be more effective than the application of foot orthoses alone in relieving foot pain in patients with plantar fasciitis.