This study examined whether sleep quality is associated with hand function above and beyond what can be explained by the effect of pain and carpal tunnel syndrome (CTS) severity on hand function in clients with CTS. The sample included 53 adults ages 30–86 yr. The Manual Ability Measure–20, Pittsburgh Sleep Quality Index, visual analog scale for pain, and electromyography for CTS diagnosis and severity level were used to measure outcomes. Sleep quality was significantly associated with manual ability after controlling for CTS severity and pain. In CTS care, attention to sleep is significant because it may promote hand function.