The 27-year-old Englishman won six times in 2000 and ended Colin Montgomerie's seven-year run at the top of the Order of Merit.
'It's a fantastic honor to be voted Player of the Year and caps a wonderful season for me and all those who have helped make it such a success,' said Westwood.
Westwood won the award unanimously over Ernie Els and Darren Clarke. The world's No. 5 ranked player is in South Africa this week for the Nedbank Sun City Challenge, which offers $2 million to the winner.