Selective mutism (SM) is an anxiety disorder that impacts communication. Children with SM present concerns to parents and teachers as they consistently do not speak in situations where there is an expectation to speak, such as at school, but speak in other settings where they feel more comfortable, such as at home. The purpose of this study was to investigate the relationship between parents’ and teachers’ perceptions of children with SM on behavioral rating scales and language measures. Forty-two children (22 boys and 20 girls, ranging from 2.4 to 13.8 years, with a mean age of 7.1 years) took part in this study. Parents and teachers completed the Behavior Assessment System for Children (BASC-3) measuring internalizing behaviors, externalizing behaviors, adaptive skills, and behavioral symptoms. Frequency of speaking and language abilities were also measured. Parents and teachers both identified withdrawal as the most prominent feature of SM but parents saw children as significantly more withdrawn than did their teachers. Both rated children similarly at-risk on scales of functional communication and social skills. Higher adaptive skills (including functional communication and social skills) were positively correlated with vocabulary, narrative language, and auditory serial memory according to teachers. Parent and teacher rating scales provide valuable information for diagnosis and progress monitoring. Children with SM can benefit from mental health practitioners who can identify and enhance their emotional well-being.