Alexis Ohanian and Alexis Olympia Ohanian Jr.
Alexis Ohanian with Olympia Ohanian Jr. Getty/Jean Catuffe
Williams' husband and their daughter have been in her box to watch both of her matches at the US Open so far.
Williams and Ohanian, a co-founder of Reddit, married in 2017. Williams gave birth to Olympia later that year.
Oracene Price
Oracene Price. Reuters//Mike Segar
Price is Serena and Venus' mother.
She coached the pair alongside their father and her former husband, Richard Williams, as youngsters.
Price and Williams divorced in 2002, after which she reverted to using her maiden name.
Tiger Woods
Tiger Woods and Serena Williams are close friends. Getty/Matthew Stockman
Woods was in Williams' box alongside his girlfriend, Erica Herman, to watch her beat Kontaveit on Wednesday.
Williams has a close relationship with the golfer and told reporters that he was "one of the reasons" she is playing at Flushing Meadows this year.
"We talked a lot, he was really trying to get me motivated," she said of Woods.
"When you can rely on someone like that, I mean, my goodness, he's Tiger Woods, it was really helpful to get clarity."
Anna Wintour
Anna Wintour. Getty/Matthew Stockman
Wintour, the editor of Vogue magazine, has been in Williams' box for both of her matches so far.
Williams announced that she would be "evolving away" from tennis after the US Open via an emotional letter published in Wintour's magazine last month.
Rennae Stubbs
Rennae Stubbs. Getty/Elsa
Stubbs, a multiple Grand Slam doubles champion, has been helping coach both Serena and Venus at the US Open.
Serena's coach Eric Hechtman; her agent, Jill Smoller; and Jamere Jenkins, one of her hitting partners have also been guests in the box.