In the 2018 general election, the Five-Star Movement was the leading party in Naples by some distance, and it received the highest share of votes in the country as a whole. Since then it has experienced some very disappointing municipal election results in Naples. The main reason for this decline lies with the competition it has faced from the «Orange Movement», a political movement created around the figure of the Mayor of Naples, Luigi de Magistris, with which it shares some basic characteristics. The two movements are on the political left, and are opposed to the political class that has ruled the municipal government and the Campania Region in recent decades. This article analyses the relationship between these two movements, by examining the results from municipal, regional, national and European elections. Moreover, through interviews with key players and an analysis of news reports, it reconstructs the movements’ characteristics and their communication strategies. Finally, by means of an analysis of electoral flows at the municipal and sub-municipal level, it estimates the exchange and sharing of voters by the two political movements.