This study examines teacher discourse strategies used in kindergarten inquiry-based science learning as part of the Scientific Literacy Project (SLP) (Mantzicopoulos, Patrick & Samarapungavan, 2005). Four public kindergarten science classrooms were chosen to implement science teaching strategies using a guided-inquiry approach. Data were collected during lesson observations; teacher discourse strategies were analyzed using qualitative and quantitative procedures. The results showed that the teachers used 13 distinct types of teacher discourse strategies in the classroom. Teacher discourse strategies were grouped into four higher levels of discourse categories. The results indicated that the nature and relative proportion of the different types of teacher discourse varied both across teacher and within teachers across classrooms.