The right to strike may be exerted in a different way depending on the law system. More often than not, the strike is the result of the employer’s refuse to perform one or another of the employees’ grievances. The present study proposes to make a configuration of these grievances, in comparative law. Which are the employees’ demands whose refusal may lead, legally, to strike, in different law systems, which are the legitimate demands and which appear as illegitimate, which demands are generally considered as reasonable and whether their qualification as reasonable or unreasonable is relevant for the strike’s legitimacy – here are some of the questions which the present study proposes to answer. Using the comparative method, but also the empirical one, practical cases of strike triggered in different European systems are analysed, with a special accent on the political demands and on the type of strike they might generate.