Newton was born in London, England, the daughter of Nyasha, a Zimbabwean health-care worker, and Nick Newton, an English laboratory technician and artist. Newton grew up as an atheist.
Her birthplace has been incorrectly reported to be Zambia in some biographies, but she has confirmed in interviews that she was born in London. The name "Thandiwe" means "beloved" in Ndebele, Zulu, Xhosa or siSwati, and "Thandie" is pronounced /ˈtændi/ in English. According to Newton, her mother is a Shona princess.
Newton was an introducer at Wembley Stadium on 7 July 2007 for the UK leg of Live Earth. She was due to introduce Al Gore to the concert, but he was delayed, leaving Newton to tell jokes in an attempt to entertain the audience. Newton next portrayed the United States President's First Daughter Laura Wilson in 2012, a disaster film directed by Roland Emmerich and released 13 November 2009.
In July 2011, Newton delivered a TED Talk on "Embracing otherness, embracing myself". In it, she discussed finding her "otherness" as a child growing up in two distinct cultures, and as an actress playing with many different selves.She was also in the movie, "For Colored Girls"  In 2012, she starred alongside Tyler Perry in the romantic drama film Good Deeds. In 2013, Thandie starred in Rogue, the first original drama series for DirecTV's Audience Network.
Newton married English writer, director, and producer Oliver Parker in 1998. They have three children: daughters Ripley (born in 2000) and Nico (born in 2004), and son Booker Jombe (born in 2014). Her daughters were named after the character Ellen Ripley in the Alien films and the singer Nico. Newton had home births with all three of her children.
In 2006, Newton contributed a foreword to We Wish: Hopes and Dreams of Cornwall's Children, a book of children's writing published in aid of the NSPCC. In it, she writes vividly about her childhood memories of growing up in Cornwall and the way in which the county's vibrant cultural heritage made it easy for her to "enrich every situation with layers of magic and meaning".
In 2007, Newton sold her near-new BMW X5 and replaced it with a Toyota Prius after Greenpeace stuck a "This gas-guzzling 4x4 is causing climate change" sticker on her BMW.
In 2008, Newton visited poverty-stricken Mali, describing it as a "humbling experience". She visited the village of Nampasso in the Ségou Region of the country.
^A Taste of My Life, Series 4 (BBC Two, 4 June 2008) Thandie Newton – Quote: "Nigel Slater (host): You were born in London but you didn't stay here for long did you? You went down to Cornwall? Thandie Newton (answers): Actually I don't know how my mum and dad managed to do this. But we lived in Zambia, and my mum was pregnant with me. And I was born on a two-week trip back to London, and then we went back to Zambia and my brother was born there. And we ended up coming to England finally when I was three years old. So my dad could help out with the family antique business."
^Thandie's Mission, Evening Standard, 22 July 2005. Quote: ...but turned down the Lucy Liu role in Charlie's Angels in favour of making It Was An Accident, a minor film by her scriptwriter husband Ol Parker.