Serena Williams has won 15 Grand Slam titles as a singles player. In addition, she has won 13 doubles titles and an additional 2 titles in mixed doubles.
venus has won seven titles. he sister Serena has won 11
She just won her fourth recently
Serena has won 12 doubles Grand Slams with her sister Venus.
34, including her 11 major titles (as of July 13, 2009)
Serena Williams has currently won 13 Grand Slam double titles with her sister, Venus Williams. They have both, however, won many more competitions on their own. Currently they are unbeaten in the Grand Slam finals.
Up until 2010 Wimbledon Championships Serena Williams has won 9 Wimbledon Championships 4 in singles 4 in doubles 1 in mixed doubles
Serena Williams won 20 waimbledon
According to my research she won her fourth on June 5 2010
For woman's tennis it is Serena Williams. For men's it is Rodger Federer. Serena has the most with 29 grand slam titles.