This chapter discusses the problems faced by the two standard theories of reference, namely descriptivist theories of reference and causal theories of reference. It defends causal descriptivism as an alternative account of the reference of the theory-dependent terms. The characterization descriptivist theories are not accidental, since the key ideas have undertaken considerable modifications over the years and in light of important philosophical controversies. Semantic holism contributed significantly to the wide acceptance of the claim that theoretical discourse is meaningful and that theoretical terms have putative factual reference. The chapter argues that a hybrid theory of reference of theoretical terms is independently well-motivated and meets in a satisfactory way conditions of an adequate theory of reference. Finally, it unravels the key difficulties of a recent attempt to dissolve the issue of the reference of theoretical terms by recourse to Ramsey sentences.