Conventional anticancer therapeutics often suffer from lack of specificity, resulting in poor therapeutic indexes and substantial toxicities to normal healthy tissues. Monoclonal antibodies have demonstrated considerable utility in cancer medicine, but their curative potential is often limited. Antibody–drug conjugates represent an innovative therapeutic approach that combines the desirable properties of monoclonal antibodies, with the cell killing activity of cytotoxic drugs, reducing systemic toxicity and increasing the therapeutic benefit for patients. In this review, we outline prominent examples of early and recent antibody–drug conjugates, discussing drugs, linker chemistries and classes of targets for product development.