The antibody response and the complement system are major effector arms of the immune system. Next to their beneficial roles in host defense, antibodies and complement are also involved in a plethora of pathological conditions—including autoimmunity, allergy and cancer—and regulate, mainly through their receptors (FcR and CR respectively) cell activation, migration, survival but also metabolism. As the portfolio of antibody—and complement-effector function grow, high-end technological solutions are developed, and novel therapeutic applications are proposed. This EMBO Workshop on Antibody & Complement will be a forum for leaders in the field and new investigators coming from academia, industry and research institutes to discuss where the field is going and what challenges lie ahead. We will focus attention on key advances in both fields with the aim at fostering discussions between antibody experts and complement experts.