A supramolecular protein tetramerization approach has been devised which enables the controlled formation of a discrete protein tetramer. The supramolecular element cucurbituril has been used as an inducer of the protein tetramerization in combination with intrinsic affinities between the proteins, which preorganize the protein in dimerized form. The combination of a dimerizing interface on the fluorescent proteins under study (dYFP, dCFP), with a genetically encoded N-terminal phenylalanine-glycine-glycine (FGG) peptide motif allows cucurbituril to selectively induce FGG-dYFP or FGG-dCFP tetramerization. The concept of cucurbituril-induced protein tetramerization was elucidated by using a combination of fluorescence anisotropy, dynamic light scattering and size exclusion chromatography experiments. The cucurbituril-induced tetrameric protein complex is formed via a "dimers of dimers" pathway, is highly stable and can be separated by size exclusion chromatography. This supramolecular induced protein tetramerization approach opens up a novel entry in generating well-defined synthetic protein assemblies.