The semiotics of science considers how linguistic resources are used to represent scientific meaning. Semiotic resources are vocabulary used to communicate sociocultural ways of understanding. Semiotic formations are institutionalized ways of communicating language. Inquiry into classroom science semiotic resources and formations examines science meaning creation and how, and what, understandings are shared. In this chapter, I consider the theoretical and analytic foundations of semiotic study of science classroom language, and trace its application in discourse analytic efforts to study teaching and learning. I consider the implications of this work for new directions in the field of social semiotics in science.