"We are applying to become a third party in the European Commission's proceeding," Sundar Pichai, Google's vice president of product management, said in a company blog.
Last month, the EU's commission submitted a preliminary list of charges, or statement of objections, to Microsoft, and accused it of shielding Internet Explorer (IE) from competition by bundling it with Windows.
Mozilla, the maker of Firefox, had earlier been granted 'interested third party' status, which allows it to submit arguments to regulators, to see the charge sheet the commission sent Microsoft and to participate in a face-to-face hearing if Microsoft requests one.
The Norwegian browser developer Opera Software filed the original complaint with the commission in late 2007.
Pichai said Google is getting involved because the field tilts toward Microsoft. "The browser market is still largely uncompetitive, which holds back innovation for users," he said.
"This is because Internet Explorer is tied to Microsoft's dominant computer operating system, giving it an unfair advantage over other browsers."
Google, which launched its own Chrome only last September, cited such features as browser tabs and privacy modes as some of the things that have appeared because of competition among browser makers.
"We believe that we can contribute to this debate," added Pichai. "We learned a lot from launching Chrome last year and are hoping that Google's perspective will be useful as the commission evaluates remedies."
Although the commission has not spelled out what actions it might demand Microsoft take, agency spokesman Jonathan Todd has provided some clues. Microsoft could be fined, forced to let users choose alternate browsers to install in Windows or ordered to allow users to disable IE if a different browser is desired.
Mitchell Baker, the former CEO of Mozilla and currently the chairman of the non-profit Mozilla Foundation, offered her take on changes Microsoft might be required to make.
In a blog, Baker, who has been commenting regularly on the issue since Mozilla joined the case as an interested party, listed several potential cures, but stopped short of calling them recommendations.
One possibility would be to make Microsoft divulge all application programming interfaces (APIs) available to IE to other browser builders, while another would be to require Microsoft to offer rival browsers whenever IE or Windows is updated, she said.
Other ideas she offered up ranged from bundling Windows with multiple browsers to including none at all. "This implementation... has some obvious drawbacks for users," Baker acknowledged.
One antitrust expert has called the EU's investigation pointless . "I just don't see what it adds to the final judgement in the US case," said William Page, the co-author of The Microsoft Case: Antitrust, High Technology, and Consumer Welfare, and a member of the faculty of the Levin College of Law at the University of Florida.
"OEMs are already free to delete most of the visible evidence of [Internet Explorer] and to install another browser if they want."
Firefox, meanwhile, held down a 21.5 percent share, while Apple's Safari and Google's Chrome ended the month with 8.3 percent and 1.1 percent, respectively.