Recently cucurbituril macrocycles attract much attention in supramolecular chemistry and have widely been used to build a variety of self-assembled nanostructures, devices, and architectures. Appropriate design of self-assembling processes requires detailed knowledge of the thermodynamics of cucurbituril complexation with various guest molecules. Despite the significant efforts devoted in recent years to the thermodynamic investigation of cucurbituril complexation, there still remain serious discrepancies in the literature data. In this review, we wish to discuss the recent achievements as well as the remaining problems in the area of complexation thermodynamics of cucurbituril.