Objective No studies have investigated sleep disturbance in avoidant/restrictive food intake disorder (ARFID). We examined sleep disturbance in ARFID and its association with eating problems, body mass index (BMI), gender, internalizing and externalizing symptoms, cognitive performance, and academic difficulties. Methods Data from 71 ARFID patients from our partial hospitalization program (PHP) for children and adolescents were examined. Sleep data were extracted from measures administered at admission including Achenbach Child Behavior Checklist (CBCL), Children's Depression Inventory (CDI), and Revised Children's Manifest Anxiety Scale (RCMAS). Correlational analyses were conducted to evaluate the convergent validity of parent-reported and participant-reported sleep problems. Association with the severity of eating problems, BMI, percentage of median body weight (% MBW), age, gender, psychotropic medication, psychopathology, and academic difficulties was examined using analysis of variance (ANOVA) and Pearson's correlation.  Results Fifty-two percent of parents and 74% of participants reported two or more sleep symptoms. Trouble sleeping was reported by 46.48% and nightmares by 35.21% of parents. Parent-reported trouble sleeping highly correlated with internalizing disorders. Parent-reported trouble sleeping and participant-reported difficulty sleeping positively correlated with attention and attention-deficit/hyperactivity disorder (ADHD) problems. Parent-reported less sleep and feeling tired correlated with sluggish cognitive tempo, while walking/talking in sleep negatively correlated with school performance. Gender differences were noted in parent-reported sleep problems. Sleep disturbances were not associated with lower BMI or median body weight at intake. Parent-reported talking/walking in sleep and participant-reported bad dreams and bedtime worries positively correlated with Children's Eating Attitudes Test (ChEAT) scores at intake and discharge. Discussion Our results provide compelling evidence to screen for sleep disturbance in ARFID patients regardless of median body weight and BMI. Exploration of sleep disturbances in ARFID using objective measures is warranted.