Immunoglobulin G (IgG) molecules are glycoproteins with dual functionality. While participating in the destruction of virally infected cells or healthy tissues during autoimmune disease, IgG antibodies are also used as a therapeutic agent to suppress IgG-triggered autoimmune disease and inflammation. Research of recent years has put the IgG-associated sugar moiety in the spotlight for regulating these opposing activities. This review will focus on how certain IgG glycovariants impact different IgG-dependent effector functions and how this knowledge might be used to further improve the therapeutic effectiveness of this class of molecules.