Antibodies are an important class of therapeutic for treating a wide range of diseases. These versatile macromolecules can be engineered to target many different antigens and to utilize several mechanisms of action to produce a pharmacological effect. The most common antibody platform used for therapeutics is immunoglobulin G (IgG). Advances in protein‐display and genetic engineering have enabled the construction and manipulation of IgG to enhance desired activity such as increasing antigen affinity, modulating pharmacokinetics, and enhancing effector functions. IgGs can also be altered to suppress undesired effects, such as immunogenicity. The main approaches to control IgG behavior include engineering the protein sequence and glycosylation of intact IgG; constructing IgG‐based derivatives, including bispecific and multivalent binders; and fusing small‐drug molecules or proteins to IgG‐derived scaffolds. Often, a single modification applied to a given IgG can alter more than one property. The desired effects of an antibody therapeutic should be carefully tailored to the physiology and characteristics of each disease condition.This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies Biology‐Inspired Nanomaterials > Peptide‐Based Structures