This study investigates language-promoting strategies and support of concept development displayed by preschool staffs' when interacting with preschool children in literacy-related play activities. The data analysed consisted of 39 minutes of video, selected systematically from a total of 11 hours of video material from six Swedish preschool units. The selected sequences were play situations where preschool staff and child/children were present and teachers used strategies for creating a high instructional climate. The results show that spontaneous play, dramatic play, adult-initiated play and child-initiated play, as well as access to objects or toys offer numerous opportunities in literacy-related play activities to support children's concept development. Results showed that during play activities, such events stimulated children's language modelling and presented opportunities to increase the preschool children's concept development. However, more research is needed in this area, especially concerning how preschool staffs' participation, timing and sensitivity help support children in literacy-related play activities.