It was created in 1919 as Waterschei's Sport Vereeniging Thor with Thor being the acronym of Tot Herstel Onzer Rechten ("To recover our rights"), later changed to Tot Heil Onzer Ribbenkas(t) ("For The Benefit Of Our Rib Cage").

The club enjoyed a spell in the first division in the late 1950s to the early 1960s and again from 1978 to 1986.

After defeating PSG in the quarter-finals, Waterschei lost the first leg of the semi-final 5–1 at Pittodrie, home of the eventual winners, Aberdeen.

A 1–0 victory in Genk, courtesy of Eddy Voordeckers, could not reverse the position.

Notable players were among others Lei Clijsters (international, and father of former tennis star Kim Clijsters), keeper Klaus Pudelko, striker Heinz Gründel, Icelandic striker Larus Gudmundsson, midfielder Pier(re) Janssen and Dutch defender and international Adrie Van Kraaij.