Muguruza is only the second Spanish woman after Arantxa Sanchez Vicario to reach number one and by claiming the Wimbledon title became the first player to beat both Serena and Venus Williams in major finals, having beaten Serena to win the 2016 French Open.
"Becoming the WTA number one in the world is a dream come true," Muguruza told the WTA's website. "Every birthday wish was always the same as I blew out the candles - to become the best.
WTA Finals
Wozniacki fends off Pliskova to reach Singapore final
28/10/2017 AT 10:44
"There is a lot of work behind this achievement and a lot of love and passion for this sport. There's also a lot of hard moments along with the great moments."
Muguruza is competing at the WTA Finals in Singapore next week.
Swiss Martina Hingis and Taiwan's Chan Yung-Jan were voted the WTA's doubles duo of the year after winning nine titles including the U.S. Open.
WTA Finals
Halep faces losing No.1 ranking as Svitolina defeat at WTA Finals
27/10/2017 AT 13:34
WTA Finals
Garcia overcomes tears to battle past Svitolina
25/10/2017 AT 17:46