Bryant, the Los Angeles Lakers guard, said in a court filing that he never gave his mother permission to sell mementos from his high school days and early professional basketball career.
Bryant is in a court battle over whether hundreds of items - from high school jerseys to trophies and championship rings - can be auctioned off.
Pamela Bryant said the NBA star told her the memorabilia was hers. She arranged earlier this year to auction it off through Berlin, N.J.-based Goldin Auctions and received a $450,000 advance.
Last week, lawyers for the son wrote to the auction house demanding it cease the June sale. Goldin is suing to assert its right to sell.
In a filing Wednesday in U.S. District Court in Camden, Kobe Bryant says his mother acknowledged to him recently that she did not have permission to sell the items. The suit was filed there because the auction house is located in southern New Jersey.
Goldin dubbed the auction "The Bryant Collection," and the main page of its website shows three Lower Merion uniforms from his high school days and one familiar No. 8 Lakers jersey. There's even a surfboard from when he won a Teen Choice award among the roughly 100 items listed.
"I never told my mother that she could have my personal property, let alone consign it for public auction," Bryant wrote in the filing.
He also posted on Twitter, "When u give Give GIVE and they take Take TAKE at wat point do u draw a line in the sand? (hash) hurtbeyondmeasure (hash) gavemenowarning (hash) love?"
According to court filings, Pamela Bryant struck a deal in January with Goldin, which earlier this year sold a rare Honus Wagner baseball card for a record $2.1 million.
She received $450,000 up front, which she intended to use for a new home in Nevada.
In its court filings, Goldin says Pamela Bryant told the auction house that she asked her son five years ago what he wanted to do with the items that were in her home.
"Kobe Bryant indicated to Pamela Bryant that the items belonged to her and that he had no interest in them," the auction house's attorneys wrote. So she put them in a $1,500-per-month New Jersey storage unit.
The challenge came Tuesday when Goldin sent a news release announcing the auction. By day's end, Kobe Bryant's lawyer had sent a cease-and-desist letter telling the auction house to call off the sale and return the items to him.
Kenneth Goldin, owner of the auction house, says he can't cancel the auction because he's already advanced $450,000 to Bryant's mother and put money into advertising the auction.
Kobe Bryant's lawyer Mark Campbell said in a statement, "Mr. Bryant's personal property has ended up in the possession of someone who does not lawfully own it. We look forward to resolving this legal matter through the legal system."
Bryant has had a sometimes icy relationship with his mother and father, Joe "Jellybean" Bryant, a former pro basketball player who is now coaching in Thailand. In the court filing, it states that the husband and wife are overseas this week.