Antibodies play a crucial role in the host's adaptive immune response, serving as key defenders against emerging and re-emerging infections. However, they can act as a double-edged sword, offering protection against disease while also potentially contributing to immune-mediated pathologies. Protective mechanisms include viral neutralization, complement activation, antibody-mediated phagocytosis, and antibody-dependent cellular cytotoxicity (ADCC), which form the basis of many effective vaccines. While antibodies can also promote disease through antibody-dependent enhancement (ADE), autoimmunity and the production of autoantibodies. This review explores the current understanding of their dual functions, using examples to illustrate the complex interactions between antibodies and pathogens. While all these factors complicate the antibody response, they also offer opportunities for targeted intervention. A deeper understanding of antibody biology is essential to inform vaccine design and therapeutic development for future infectious disease threats.