William VI Bertrand II (died 1093[1]) was count of Provence following the death of his father Fulk Bertrand, though he is not mentioned until the next year (1063). Fulk was either the eldest or second eldest son of Geoffrey.
There is much confusion concerning the last counts of Provence of the first and native dynasty. Both Geoffrey I and his brother Fulk Bertrand had sons named either William or Bertrand. It seems that Bertrand's cousin, Bertrand I, ruled as marchio (margrave) until his death around 1094 and was succeeded in his titles by Raymond IV of Toulouse.
By his wife Matilda, he had one daughter Cecilia, who married Bernard Ato IV, Viscount of Carcassonne.