The synthesis of metal–organic frameworks (MOFs) has, to date, largely been in the form of crystalline powders. However, interest in different physical morphologies of this class of materials is growing. In this perspective, we provide an overview of the structure, properties and applications of MOF monoliths. In particular, we explore the complex synthetic landscapes associated with MOF crystallization and discuss the synthetic factors leading to the formation of MOF gels, i.e. the precursor to sol–gel MOF monoliths. Finally, we provide our thoughts on the future development of this field, and attempt to highlight the importance of the MOF gel state in the discovery of new functional materials.