Both tech firms have drawn criticism over their involvement in controversial military and police projects, prompting anonymous workers to write public letters denouncing them.
The protests come after Amazon CEO Jeff Bezos said that part of his job is to make unpopular decisions, such as choosing to work with the US military or providing tools that enable police surveillance.
In response, an Amazon employee wrote in a post published to Medium: "Companies like ours should not be in the business of facilitating authoritarian surveillance. Not now, not ever."
It follows a similar letter shared publicly in June, when people working for Amazon wrote to Mr Bezos to protest the sale of the facial recognition tool to police departments and government agencies.
"As ethically concerned Amazonions, we demand a choice in what we build, and a say in how it is used," they said. "We learn from history, and we understand how IBM's systems were employed in the 1940s to help Hitler."
Microsoft employees also protested their company's work with the US government, after the company expressed interest in the $10 billion JEDI contract to provide cloud services to the US Department of Defense.
"Many Microsoft employees don't believe that what we build should be used for waging war," the letter, published to Medium on Friday, stated.
Earlier this year, more than 100 workers signed a letter addressed to company CEO Satya Nadella about another controversial contract with US Immigration and Customs Enforcement (ICE).
The letter called for Microsoft to take an ethical stand and "put children and families above profits," following a zero tolerance policy on the part of the agency that resulted in children being separated from their parents.
"We ask that Microsoft cancel its contracts with US Immigration and Customs Enforcement (ICE) immediately, including contracts with clients who support ICE," the letter stated.
"We also call on Microsoft to draft, publicize and enforce a clear policy stating that neither Microsoft nor its contractors will work with clients who violate international human rights law."
Mr Nadella responded by calling the border policy "cruel and abusive" and a corporate blog post stated that the company would not work on any projects related to separating children from their families at the border.
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