Maria Sharapova is in the Women's Tennis Association.
Maria Sharapova . A United States resident since 1994 , Sharapova has competed on the WTA tour since 2001 . She has been ranked world No. 1 in singles by the WTA on five separate occasions , for a total of 21 weeks . Venus Williams . Ranked World No. 11 in singles as of January 28 , 2017 , Williams has been ranked World No. 1 by the Women 's Tennis Association on three occasions , for a total of 11 weeks . The Women 's Tennis Association ( WTA ) , founded in 1973 by Billie Jean King , is the principal organizing body of women 's professional tennis .