 The term “theory of meaning” has figured, in one way or another, in a great number of philosophical disputes over the last century. Unfortunately, this term has also been used to mean a great number of different things.  In this entry, the focus is on two sorts of “theory of meaning”. The first sort of theory—a semantic theory—is a theory which assigns semantic contents to expressions of a language. The second sort of theory—a foundational theory of meaning—is a theory which states the facts in virtue of which expressions have the semantic contents that they have.  Following a brief introduction, these two kinds of theory are discussed in turn.