ABSTRACT Objective Parent–Child Interaction Therapy (PCIT) is a parenting program in which caregivers must achieve “skill criteria” in using Do Skills and avoiding Don’t Skills to complete treatment. Despite PCIT’s emphasis on these skills, little is known about how Latinx caregivers acquire these Western-based parenting practices and whether cultural mismatches lead to inequities in outcomes. This study compared the trajectories of change in PCIT skills and treatment outcomes of Latinx and non-Latinx White families. Method We analyzed weekly treatment data from 64 families (20.3% Spanish-speaking Latinx, 51.6% English-speaking Latinx, 28.1% non-Latinx White) served in community clinics. Caregivers were mostly females (95.3%), on average 35.13 years old, and lived in poverty (77.6%). PCIT skills were coded using the Dyadic Parent–Child Interaction Coding System, and child behavior problems were reported using the Eyberg Child Behavior Inventory. Results Latinx and non-Latinx White caregivers acquired Do Skills similarly during treatment. In contrast, some Latinx caregivers began treatment using significantly more Don’t Skills and needed more sessions to achieve some aspects of PCIT skill criteria compared with non-Latinx White caregivers. Latinx families also experienced similar or even more pronounced reductions in child behavior problems than non-Latinx White families. There were no significant differences in the percentage of caregivers who achieved PCIT skill criteria or left treatment prematurely. Conclusions This study provides evidence that strictly defined PCIT skill criteria may lead to inequities in treatment length for some Latinx families. Informed by these findings, we propose data-driven adaptations to improve the cultural fit of PCIT for Latinx groups.