Avoidant/restrictive food intake disorder (ARFID) is characterized by food avoidance or dietary restriction not primarily motivated by body weight/shape concerns. Individuals with ARFID can report early satiation, post-prandial fullness, and high intermeal satiety, but whether these symptoms are related to differences in the biology underlying appetite regulation is unknown. In male and female children and adolescents, we hypothesized that fasting levels of cholecystokinin (CCK), a satiety hormone, would be elevated in participants with ARFID (full or subthreshold) versus healthy controls (HCs). Within the ARFID group, we also explored the relations of CCK with weight status, subjective appetite ratings, and ARFID severity and phenotypes.