Colleen "CoCo" Vandeweghe (/ˈvændəweɪ/ VAN-də-way) (born December 6, 1991) is an American professional tennis player. A former Junior US Open champion at the age of 16, she has also won two WTA titles, both at the Rosmalen Grass Court Championships in Den Bosch. In 2017, she reached two Grand Slam semifinals and the final of the WTA Elite Trophy to move up to a career-high ranking of No. 9. In addition to her two Grand Slam semifinals in 2017 at the Australian Open and the US Open, Vandeweghe has twice reached the quarterfinals at Wimbledon, in 2015 and 2017.
Despite being predominantly a singles player, she also excels at doubles. In 2016, she partnered with Martina Hingis in much of the second half of the season and reached the semifinals of the US Open, a performance that lifted her to a career-high ranking of No. 18 in the world. In that year, she also reached two Grand Slam mixed-doubles finals, at the Australian Open and at the US Open. In 2018, Vandeweghe won her first Grand Slam title; partnering Ashleigh Barty she won the women's doubles title at the US Open.