The onset of selective mutism (SM) is usually between the ages of three and five years, when the children first go to preschool. However, these children are most commonly referred for treatment between the ages of six and 11, when they are entering the elementary school system. Early detection and early intervention is suggested for effective SM treatment and to prevent long-lasting complications, such as socialization and learning problems. This article presents a brief literature review of SM; intervention approaches that have been used; and one SM case study that includes intervention strategies, experiences, and lessons learned from working with a child with SM. The authors' goal was to provide school social workers and teachers with a better understanding of the features of children with SM to enable early detection and early intervention in preschool and early grades in elementary school.