The former champions had Venezuelan state oil company PDVSA as their biggest sponsor until Venezuelan Pastor Maldonado left at the end of last season.
"Petrobras and Williams have had a successful partnership before and we are both looking forward to reuniting for 2014," said founder Frank Williams in a statement.
"Technologically they are very strong and that will be important for the team as the new regulations have made fuel efficiency increasingly important."
- Sports & Recreation
- Pastor Maldonado
- Felipe Massa