The reality star has been strongly criticised for vocally backing Trump over the last few years, but has now admitted she regrets doing so.
Her withdrawal of support follows a leaked government memo proposing fundamental changes to the way gender is defined in law, which will have huge ramifications for the trans and non-binary community.
In response, Caitlyn, who came out as trans in 2015, published an op-ed in the Washington post, titled ‘I Was Wrong’.
She wrote: “Trump was the first Republican presidential candidate to claim to support this valuable, vulnerable community, and I was encouraged by the applause he received when he said at the Republican National Convention in July 2016 that he would stand up for the LGBTQ community.
“Sadly, I was wrong.”
Caitlyn went on to accuse Trump of treating the trans community as “political pawns”.
“The reality is that the trans community is being relentlessly attacked by this president,” she said.
“The leader of our nation has shown no regard for an already marginalized and struggling community. He has ignored our humanity. He has insulted our dignity.
“He has made trans people into political pawns as he whips up animus against us in an attempt to energize the most right-wing segment of his party, claiming his anti-transgender policies are meant to ‘protect the country.’
“This is politics at its worst. It is unacceptable, it is upsetting, and it has deeply, personally hurt me.”
Caitlyn is not the only high-profile figure to lambast Trump over his proposals, which would mean trans people would not be able to change their gender in legal terms later in life.
Lady Gaga accused him of being “being driven by ignorance” in an attack on Twitter earlier this week.
The singer, who has always been a passionate defender of LGBTQ rights, tweeted: “The government may be living in an alternate universe, but we as a society & culture know who we are and know our truth and must stick together and raise our voices so we can educate them about gender identities.
“While today you might feel unheard or unseen, know that this is not the reality of humanity. This is another display of leadership being driven by ignorance. #TransRightsAreHumanRights #WontBeErased.”