Although previous research provides insights into how gestures function as a pedagogical tool, relatively little is known about how gesture is related to language, together creating a key meaning-making teaching resource. Drawing on the system of logico-semantic relations in Systemic Functional Linguistic theory and McNeill's description of gestures, this study examines how gesture is logically and semantically related to the language teachers use in elementary science classrooms. The study is primarily qualitative in nature and uses video recordings as the primary data. The main purpose is to analyze the kind of gesture-speech relations used by elementary science teachers and to develop a system network that describes gesture-speech relations in elementary science teaching. Distribution of the gesture-speech relations shows that some relations are more likely used to teach scientific knowledge, some are more likely used for classroom management, and some are used for both.