The surveillance of tumors by the immune system of cancer patients and its impact on disease progression and patient survival have been largely documented over the last years. In parallel, the use of therapeutic monoclonal antibodies (mAbs) in oncology has gained a widespread recognition as it has made it possible to increase patient survival and to ameliorate the quality of life in a number of cancers. However, the clinical responses observed following mAb treatment remain largely heterogeneous and their duration is still highly unpredictable. Recently, the concept that the injection of therapeutic antibodies not only triggers early anti-tumor events such as receptor blockade, cytostasis, apoptosis, complement-dependent cytotoxicity and/or antibody-dependent cytotoxicity but also allows the host immune system to fight tumor cells through the development of a long-lasting adaptive immunity has emerged. In the present review, we will examine the arguments that support this concept by detailing the cellular and molecular events likely to underlie the induction of an efficient anti-tumor adaptive immune response by mAbs. We will also discuss the consequences of this induction on the way therapeutic antibodies can be used and inserted in a more global immunotherapeutic approach aiming at strengthening the adaptive anti-tumor immune response developed by cancer patients.