Amazon declined to comment on Trump's tweet Thursday.
Trump's use of social media to call out individual people and companies has been unprecedented for a president. His other Twitter targets have included Apple, Boeing and General Motors, as well as media outlets including The Washington Post, the New York Times and CNN.
The president has long been vocal with his disapproval of Amazon.
Trump has frequently complained about Amazon and Jeff Bezos to his friends, according to people who have spoken with the president. For example, at a dinner last month at Mar-a-Lago with Fox News personality Geraldo Rivera and the president's two adult sons, Donald Jr. and Eric, Trump brought up Amazon and said they should pay more in taxes, according to a person familiar with the dinner.
In December, Trump attacked the company's arrangement with the U.S. Postal Service and called on the agency to raise the shipping rates it charges Amazon.
"Why is the United States Post Office, which is losing many billions of dollars a year, while charging Amazon and others so little to deliver their packages, making Amazon richer and the Post Office dumber and poorer?" he tweeted. "Should be charging MUCH MORE!"
His tweets about the USPS reflect a debate about whether the Postal Service is charging Amazon and other retailers enough to deliver packages. Parcel delivery has become an increasingly important part of the Postal Service's business as first-class mail has been on a long-running decline.
Amazon's partnership with the U.S. Postal Service is reviewed annually by the Postal Regulatory Commission, an oversight agency that also sets the rates that Amazon pays for shipping. Experts say that, by law, the USPS must charge rates that are profitable for them. Last year, the postal service reported profits of $7 billion and $20.7 billion in revenue.
Earlier in his presidency, Trump tweeted that "Amazon is doing great damage to tax paying retailers. Towns, cities and states throughout the U.S. are being hurt - many jobs being lost!"
(When it comes to his own income taxes, however, the president seems to have a different take. Not paying federal income taxes "makes me smart," he said during a presidential debate in 2016.)
Before becoming president, Trump criticized Amazon's "monopolistic tendencies" and said the company could face "a huge antitrust problem" because "Amazon is controlling so much." The retailer, which last year had $177.9 billion in revenue, has more than half a million employees worldwide. The company purchased Whole Foods Market for $13.7 billion last year, in a deal approved by the Federal Trade Commission.
Trump has also suggested that The Post is "a lobbyist weapon against Congress to keep Politicians from looking into Amazon no-tax monopoly."
The Post's editors and Bezos have declared that Bezos is not involved in any journalistic decisions. The Post is owned by Bezos personally, not by Amazon.