The properties of the isoscalar giant monopole resonance (ISGMR) in the Ca isotope chain are analysed in the framework of a microscopic model based on a Skyrme interaction. The effects of the coupling between one-, two- and three-phonon terms in the wave functions of 0⁺ states have been studied. Using the same set of parameters, we describe available experimental data. The effects of the phonon-phonon coupling leads to a redistribution of the main monopole strength to lower energy states and also to higher energy tail. It is shown that the gross structure of the ISGMR in the calcium isotopes ^{40,42,44,46,48}Ca is caused by the complex configurations.