Williams, who did not attend the event, won the U.S. Open last year and reached the Wimbledon final. She also claimed a gold medal with sister Venus in the doubles at the Beijing Olympics.
In her career, the American has claimed ten grand slam titles and she was also the WTA Player of the Year in 2002.
“Winning the Player of the Year award for the second time in my career is a great personal achievement,” Williams said in a statement released by the WTA.
Cara Black of Zimbabwe and Liezel Huber of South Africa won the doubles Team of the Year award.
Russia’s Dinara Safina was Most Improved Player of the Year after finishing the season ranked second while China’s Zheng Jie was awarded Comeback Player of the Year, after returning from injury to climb over 100 places in the rankings.
Denmark’s Caroline Wozniacki was Newcomer of the Year after picking up three wins on tour while Serbian Ana Ivanovic was named Humanitarian of the Year for her work with the United Nations Children’s Fund.