Past studies show that emotional socialization and family accommodation are involved in children's anxiety, but research has yet to investigate whether targeting emotional socialization training (EST), family accommodation modification (FAM), or EST and FAM in tandem can reduce anxiety in children. The purpose of this study was to evaluate the efficacy of a combination of EST and FAM on improving emotion regulation (ER) and reducing anxiety symptoms in anxious children. The sample consisted of 80 children with an anxiety disorder (Mage = 6.7, SD = 0.1) and their mothers. Mothers were randomly assigned to an EST (n = 17), FAM (n = 16), Combined (n = 17), or a waitlist control (WLC) (n = 16) groups. Mothers completed The Emotion Regulation Checklist (ERC) and Spence Children’s Anxiety Scale (SCAS) at pre-test, post-test, and at 6-month of follow-up. The results showed that the EST, FAM, and Combined groups were more effective than WLC in improving ER and reducing anxiety severity at post-test and follow-up. Among the intervention groups, children in the combined group showed greater reductions in the severity of anxiety symptoms and emotion dysregulation than the other two groups. Assisting parents to use strategies that encourage healthy emotion regulation and decrease family accommodation might help reduce the severity of children's anxiety symptoms.