This paper tackles the question of regionalist parties, a quite underdeveloped aspect of the literature, even if the phenomenon is of increasing importance in European democracies. In that sense, Belgian regionalist parties (VU, FDF and RW) are an interesting case study. They recorded significant success in the 1960s–1970s. Yet, three decades later, they disappeared or declined severely. This paper shows how this ‘Icarus’ fate’ is explained by the fact that Belgian regionalist parties were victims of their own success. After having demonstrated the incomplete and indirect success of these parties using Harmel’s dimensions, this study demonstrates how this success turned all favourable indicators red, leading to the decline and extinction of the three regionalist parties. ; info:eu-repo/semantics/published