Objective: Although cognitive behavioral treatments (CBTs) are well-established evidence-based interventions for anxiety disorders in youth, there is long-standing underrepresentation of Hispanic/Latino (H/L) families in youth anxiety clinical trials research. The impact of such underrepresentation is that clinicians who work with H/L youth have minimal evidence-based guidance on best practices. The present study moves toward informing best practices for working with H/L youth with anxiety disorders by examining H/L parents' acculturation and enculturation as moderators of youth anxiety outcomes following CBTs. Method: Two hundred eleven H/L youths ages 6-16 (M = 9.41 years, SD = 2.39 years; 43.8% female) and their parents were assigned to individual-youth CBT or one of two parent involvement CBTs: one targeted decreasing parent psychological control, the other targeted decreasing parent use of negative reinforcement. Parent acculturation and enculturation were measured at pretreatment; youth anxiety severity was measured at pretreatment, posttreatment, and 12-month follow-up evaluations. Results: Youth anxiety outcomes were enhanced in both parent involvement CBTs compared with individual-youth CBT. Parent acculturation, but not enculturation, significantly moderated outcomes. At lower levels of parent acculturation, youth anxiety outcomes were enhanced in the parent involvement CBT that targeted negative reinforcement. At higher levels of parent acculturation, youth anxiety outcomes were enhanced in the parent involvement CBT that targeted psychological control. Conclusions: These findings further support the efficacy of CBTs for anxiety disorders in H/L youth and suggest guidance for tailoring parent involvement treatments based on parent acculturation levels. What is the public health significance of this article? This study advances best practices for treating Hispanic/Latino (H/L) youth with anxiety disorders by demonstrating that (a) parent involvement in cognitive behavioral treatments enhances youth anxiety outcomes and (b) parent acculturation levels moderate outcomes. For low-acculturated parents, targeting decreases in negative reinforcement enhances outcomes; for high-acculturated parents, targeting decreases in psychological control enhances outcomes.