The 86-year-old writer has chronicled the doings of the rich and famous for New York tabloids for more than three decades.
"The Post is grateful to have been able to publish Liz Smith's legendary column for so many years. We wish her the very best for the future," New York Post Editor Col Allan said in a statement issued Tuesday.
Smith told CNN affiliate WABC-TV in New York that Friday "will be the first time in 33 years that there hasn't been a Liz Smith column in a New York paper."
"That hurts my heart. I would hate to see another newspaper fail. ... When I came to New York, there were nine newspapers. I've worked for seven of them. They just disappear out from under you," said the columnist, who has also worked for the New York Daily News and Newsday.
Smith will write a column five times a week for wowOwow.com, an online community created and run by women for women, starting next week, CNN said.