This study examined maintenance of treatment effects in a culturally tailored parent education program for Latinx families of children with autism spectrum disorder using a behavior maintenance framework. In a two-site randomized waitlist-control study, we compared differences in parent and child outcomes across three timepoints using linear mixed models to determine whether outcomes observed at 4 months after baseline (Time 2) were maintained for an additional 4-month period (Time 3). Parent outcomes included family empowerment, self-reported confidence in, and frequency of using evidence-based strategies. Child outcomes included parent-reported challenging behaviors, social communication impairments, and the number of services received. Participants were 109 Latina mothers (intervention = 54, control = 55) of children with autism spectrum disorder. Results showed that at Time 3, mothers in the intervention groups reported significantly greater confidence in and frequency of using evidence-based strategies, and that their child received significantly more services. Site-specific treatment differences were found in outcomes such as parent-reported empowerment and child social communication impairments. Findings suggest that the intervention for Latinx parents of children with autism spectrum disorder was efficacious and could be maintained, and that site-specific policy and service differences may need to be examined in future research to inform dissemination and implementation.