Biochar is the black residue remaining after the pyrolysis of biomass. It has a pore structure with large specific surface area, accompanied by a strong adsorption capacity. Due to its mesoporous framework, biochar can be used to shape stabilize the phase-change materials (PCMs). A PCM is a substance absorbing and releasing thermal energy at a phase transition. Therefore, biochar and PCMs are producing composites which can be useful for heating and cooling applications. Here we propose a discussion of recent literature about development and applications of biochar-based composite PCMs. In particular, the literature about the role of biochar mesopores in the encapsulation of PCM is highlighted.