The aim of this research was to determine the quality of sleep, reasons for sleep disturbances, and nonpharmacological strategies versus sleep disturbances of cancer patients' family caregivers. A descriptive, cross-sectional study design was used. Ninety family caregivers were included. Data were collected using the Pittsburgh Sleep Quality Index (PSQI), demographic data form, and open-ended questions about reasons for sleep disturbances and nonpharmacological strategies used by family caregivers. Descriptive statistics, Kruskal-Wallis variance analysis, and Bonferoni-corrected Mann-Whitney U test were performed using SPSS program. The PSQI score of 72.22% of the caregivers was above 5, which indicated poor sleep quality. The most commonly determined reasons for sleep disturbances were "emotional distress because of the patient's illness" (83.33%), "financial problems" (36.66%), and "inadequate support system" (34.44%); 76.92% of caregivers used at least 1 nonpharmacological strategy, which included mostly "lifestyle practices" (54.28%) and "behavioral practices" (25.71%). The total PSQI scores of caregivers having an illness were significantly higher than those of caregivers having no illness (Z = 3.230; P = .001). Total PSQI scores did not differ by sex, age, education, marital status, or duration of caregiving (P > .05). This study implies that caregivers are in need of support by healthcare professionals to provide a positive environment during the care process.