This chapter reviews issues surrounding theories of reference. The simplest theory is the “Fido”-Fido theory - that reference is all that an NP has to contribute to the meaning of phrases and sentences in which it occurs. Two big problems for this theory are coreferential NPs that do not behave as though they were semantically equivalent and meaningful NPs without a referent. These problems are especially acute in sentences about beliefs and desires - propositional attitudes. Although Frege’s theory of sense, and Russell’s quantificational analysis, seem to solve these problems for definite descriptions, they do not work well for proper names, as Kripke shows. And Donnellan and Strawson have other objections to Russell’s theory. Indexical expressions like “I” and “here” create their own issues; we look at Kaplan’s theory of indexicality, and several solutions to the problem indexicals create in propositional attitude contexts. The final section looks at indefinite descriptions, and some more recent theories that make them appear more similar to definite descriptions than was previously thought.