Waleran III (or Walram III) was initially lord of Montjoie, then count of Luxembourg from 1214. He became count of Arlon and duke of Limburg on his father's death in 1221. He was the son of Henry III of Limburg and Sophia of Saarbrücken.
As a younger son, he did not expect to inherit. He carried on an adventurous youth and took part in the Third Crusade in 1192. In 1208, the imperial candidate Philip of Swabia died and Waleran, his erstwhile supporter, turned to his opponent, Otto of Brunswick. In 1212, he accompanied his first cousin Henry I, Duke of Brabant, to Liège, then in a war with Guelders. Waleran's first wife, Cunigunda, a daughter of Frederick I, Duke of Lorraine, died in 1214 and in May he married Ermesinda of Luxembourg, and became count jure uxoris there. Ermesinda claimed Namur and so Waleran added a crown to his coat of arms to symbolise this claim.
In 1221, he inherited Limburg and added a second tail to the rampant lion on his arms. This symbolised his holding of two great fiefs. In 1223, he again tried to take Namur from the Margrave Philip II. He failed and signed a peace treaty on 13 February in Dinant. He then took part in various imperial diets and accompanied the Emperor Frederick II into Italy. Returning from there, he died in Rolduc.