TV Line said she will replace Weeds actress Mary-Louise Parker who was originally hired, but has had to pull out while recovering from pneumonia.
Thurman will take over the role of Anouk, a TV writer who is dating her show's young leading man.
The Slap charts the fallout after a man slaps another couple's child.
Published in 2008, the Booker-longlisted novel was previously made into an Australian mini-series in 2011 starring British actress Sophie Okonedo and former Home and Away star Melissa George.
George will also star in NBC's eight-part mini-series, reprising her role as overprotective mother Rosie.
Thandie Newton will take up the role first played by Okonedo, with Brian Cox, Peter Sarsgaard and Star Trek's Zachary Quinto also starring in the series.
Quinto will play Harry, the person who deals the fateful slap at a family barbecue.
Lisa Cholodenko, the Oscar-nominated director of The Kids Are All Right, is attached to direct the series.
It will be Thurman's second foray into television - she appeared in five episodes of musical drama Smash in 2012.
She most recently starred Lars von Trier's two-part big screen drama Nymphomaniac.
Uma Thurman has been cast in the US TV version of Christos Tsiolkas's best-selling novel The Slap, according to reports.