The companies are accused of deceiving customers by selling unlicensed software, or selling software under student or volume licences to customers that were not eligible for such discounts.
Some of the dealers are also accused of selling illegal Certificate of Authenticity labels that were improperly separated from their original software packages.
"The legal actions announced today are part of our ongoing commitment to protect consumers and support our partners by preventing dishonest dealers from selling unlicensed software," said Bonnie MacNaughton, senior attorney at Microsoft.
"The unlawful distribution and sale of this software has tangible negative consequences for the marketplace.
"It undermines Microsoft's legitimate partners and deceives customers who think they are receiving the full value of what they paid for, but instead receive unlicensed software."
Microsoft is also working to identify and remove the source of illegal unlicensed software, and has taken action in one of its lawsuits against an alleged source for unlicensed software in the Netherlands.
This action follows information from a number of software dealers in the US which settled prior lawsuits for selling unlicensed software.
Microsoft has alleged that HW Trading BV and its principal, Samir Abdalla, received more than US$3.7 million from just three dealers in the US between March 2006 and May 2007 in payment, in whole or in part, for unlicensed software.
A second source of unlicensed software alleged to be exploiting the Egyptian government's PC Initiative was raided by Egyptian law enforcement authorities on 30 April.
Computers loaded with unlicensed software, counterfeit software and software components, and various other unlicensed software products, were confiscated in the raid.