The Swiss VET, in its current institutional form, was gradually established over a 50-year period between 1880 and 1930. Beside the Confederation and the Cantons, the third main actor in this institutionalisation process can be identified in professional associations in the craft sector. On the contrary, trade unions play a minor role in the all process. The paper presents the main reasons that could explain the discreet presence of trade unions in the process of institutionalization of the domain and analyses the consequences of this on the first laws on VET and on the successive evolution to the present day.