The duo are giving people a peek behind the scenes at their lives in the six-part series, which was unveiled on Thursday (8 December).
But Morgan, who has made his feelings about the pair clear on many occasions, was unimpressed and let rip with a string of tweets.
The broadcaster, 57, posted: "This is worse than Keeping Up With The Kardashians. Something I didn’t think was humanly possible."
This is worse than Keeping Up With The Kardashians. Something I didn’t think was humanly possible. #HarryandMeghanonNetflix
— Piers Morgan (@piersmorgan) December 8, 2022
He also branded it "so boring".
"Disgusting how they’re repeatedly trying to brand Britain a racist country," he went on.
"Most tolerant place in Europe, as all the coverage of their engagement/wedding showed."
Morgan has previously taken issue with the pair talking about people hearing their story from them, saying in a recent column in The Sun that they had actually shared their story many times.
He returned to the issue on Twitter, tweeting a string of crying with laughter emojis as he said: "We’ve never been allowed to tell our story until now."
The TV star said that he would be discussing the documentary in a special instalment of his Uncensored show.
"Tune into tonight for a special edition on this grotesque #HarryandMeghanNetflix whine-a-thon," he told his followers.
Morgan has made his thoughts on the royals clear several times.
Last year he walked away from Good Morning Britain after refusing to apologise for saying he didn’t believe some of the things the Duchess of Sussex said in her interview with US chat show host Oprah Winfrey.
Watch: Piers Morgan blasts Harry and Meghan's new Netflix documentary