The use of antibodies for treating infectious diseases has a rich scientific history stemming back to the early 20th century. Since their initial discovery, scientists have developed numerous technologies to leverage the power of antibodies as therapeutic reagents. This relies heavily on finding the ideal antigen and antibody binding pair to stimulate an immune response. Today, antibody therapies treat a plethora of ailments, from drug-resistant infections to emerging pathogens, such as SARS-CoV-2. Uncover the history of antibody immunotherapeutic research and how scientists today develop new antibodies therapies to treat infectious diseases.