This study aims to examine the effect of the psychoeducation program on reducing the state and trait anxiety levels of mothers with children with autism spectrum disorder (ASD). This research is a quasi-experimental study using the pre-test post-test control group design. The study group consists of 20 mothers, who have children with ASD diagnosis and whose children attending Konya / Selçuklu Autism Education Foundation (SOBE). The psychoeducation program was applied to the mothers in the experimental group for 8 weeks. No procedure was applied to the mothers in the control group. Spielberger State and Trait Anxiety Inventory (STAI) and personal information form developed by the researcher to collect some socio-demographic information were used as data collection tools in the study. The pretest and posttest scores of the mothers in the experimental and control groups were compared with the dependent and independent groups t-test. As a result of the analysis of the data, it was found that there was a significant difference between the state and trait anxiety pre-test and the post-test mean scores of the mothers in the experimental group.