Play and peer interactions are crucial for children’s socioemotional development and growth. However, children with special needs, disabilities, and developmental delays may not participate in play with peers as much as typically developing children. Reliable and valid assessment information of children’s social behavior is necessary to design programs that support the socioemotional development of young children with and without special needs. The Teacher Impression Scale (TIS) is a behavioral rating scale based on systematic observations of children’s social behaviors in play. The study aimed to examine the internal structure evidence and the reliability of the Swedish version of the TIS. A sample of 46 preschool teachers used the TIS to rate the social behavior of 92 children. Teachers observed children with special education needs (SEN) and typically developing children (TD) during a 2-week time to assess the children’s social interactions in different play situations. The results showed that the Swedish version of the TIS, hereafter called TIS-S is reliable and can help teachers to identify the need of support for children in play and social interaction in inclusive preschool environments. Furthermore, the instrument could also be useful for identifying special educational strategies aimed at strengthening the social interaction between children.