A new inventory assessing thought-action fusion (TAF) in children is presented. We explore the psychometric properties of this instrument and examine the associations between TAF, ritualistic and compulsive-like behavior (CLB) and anxiety. Three hundred thirteen children ages 7–14 (M = 10.16, SD = 1.92) representing six grades (grouped into three grade levels (grades 2–3, 4–5, and 6–7) completed the Thought-action Fusion Inventory for Children (TAFIC) and the Child Revised Manifest Anxiety Scale. One hundred thirty-five parents or guardians completed the Childhood Routines Inventory. Results revealed high internal consistency in the TAFIC (Cronbach’s α = .92). TAF scores changed with age: Older children reported less TAF than younger children. Stepwise multiple regression analyses revealed that: (1) physiological anxiety predicted CLB in early childhood; (2) TAF predicted CLB in older children. Consistent with structural developmental theories, TAF changes throughout development, but plays a role in the normative regulation of affective states, as well as in the development of ritualistic compulsive like behavior in children.