The history of the Italian party system until 2011 could be split into two main phases: one characterized by a “polarized multipartism”, and one started in the mid-1990s and characterized by a bipolar competition between two major coalitions of parties. After a long period of “fragmented bipolarism”, the 2013 general election saw the fall of the mainstream parties which had alternated in government until then and the emergence of a new strong third political force, namely the Five Star Movement. This result challenged the new bipolar structure that Italy had acquired and generated a major political crisis which eventually led to the creation of a grand coalition composed of the two former political competitors from the centre left and the centre right. These political events are not dissimilar from what happened in many other European democracies in recent times – crisis of the governing parties, success of new political actors, restructuring of the party system – and bring about a crucial question that will drive the present work: can we speak of the launch of a third new phase in the Italian party system following the 2013 – and then the 2018 – elections? And what are the main causes of such change?