The 1981 Avon Championships World Championship Series was the 10th season since the foundation of the Women's Tennis Association. It commenced on January 4, 1981, and concluded on December 19, 1981, after 36 events. The Avon Championships World Championship Series was the elite tour for professional women's tennis organised by the Women's Tennis Association (WTA). The year is divided into two sponsors with the first three months sponsored by Avon Series and the latter part by Toyota Series. It included the four Grand Slam tournaments and a series of other events. ITF tournaments were not part of the tour, although they awarded points for the WTA World Ranking.