Behavioral scores by diagnosis and GI group for (a) Repetitive Behavior Scale, (b) Social Responsiveness Scale, (c) Short Sensory Profile, (d) Child Behavior Checklist and (e) Children's Sleep Habits Questionnaire. Children in both diagnostic groups with co‐occurring GI symptoms had more severe scores in multiple measures across all domains. A/V,auditory/visual sensitivity; Aggr, aggressive behavior; Anx/Dep, anxious/depressed; Atten, attention problems; AudF, auditory filtering; BedR, bed resistance; Breath, breathing problems; CRSB, compulsive/ritualistic/sameness behaviors; DaySl, daytime sleepiness; EmRx, emotional reactivity; LE/W, low energy/weak; Mov, movement sensitivity; Para, parasomnias; RRB, restrictive and repetitive behaviors; RSB, restrictive stereotyped behaviors; SCI, social communication and interaction; SIB, self‐injurious behaviors; SlAnx, sleep anxiety; SlDur, sleep duration; Sleep, sleep problems; SlOns, sleep onset delay; SlWalk, sleep walk; SomC, somatic complaints; Ta/Sm, taste/smell sensitivity; Tac, tactile sensitivity; U/SS, underresponsive/seeks sensation; Withdr, withdrawn