Cox won gold in London 2012, making her the first UK woman to win two medals at the same Paralympics.
In Brazil last year, she came second in the T38 4x100m, losing out to Jessica Ennis-Hill, who went on to win gold in Rio, and won silver in the T38 100m final – her only individual medal of Rio 2016.
Some see the Paralympian as less of a certainty to win in Australia than David Beckham, who triumphed in the first series in 2007.
Cox says she will not take any part in the ITV reality show.
She said she would continue to focus on her training and the 2020 Paralympics in Tokyo.
The 26-year-old was born with cerebral palsy and without the use of her legs. She became the first British Paralympian to compete at three consecutive Games.
Former Olympic champion Dame Tanni Grey-Thompson said Cox could win the show but was unhappy with her decision to give up the chance to train with some of Britain’s biggest track and field stars.
“There is not a track and field coach anywhere that would make her use that speed advantage or you would actually be supporting her being in the jungle,” she said.
“There is no way I would. I just think it is putting everything back together again that is going to make her a phenomenal athlete and it will be great for her.”
Tanni Grey-Thompson (right) has been critical of Cox’s decision to take part in the show
Cox initially turned down a £50,000 appearance fee in favour of receiving £1 a day.
Cox tweeted earlier this week that this offer was “too good to turn down” – but she said after a discussion with her representatives and her family, that she had withdrawn from the show.
The season will start on 19 November and will run for 10 weeks.