Climate change has driven attention toward promoting sustainable policies and processes to contain global warming below +1.5 °C. Negative emission technologies (NET)�bioenergy with carbon capture and storage in particular (BECCS)�are expected to contribute to the achievement of that target. Recent research and development concerning NET focused on chemical looping combustion (CLC) and chemical looping gasification (CLG), as they should limit cost-and energy-penalties associated with carbon capture and storage thanks to solid materials known as oxygen carriers (OCs). This review aims to provide an introductory tool about CLC and CLG and their possible role as NET if fed with biomasses to obtain BECCS. A critical overlook is proposed concerning chemical looping reactions, fuels, types of OCs, and reactor systems developed at different scales, focusing on recent and current European research projects and remarks on the subsequent developments.