Many of the internet search giant's 10,000 employees are being urged to move to alternative systems including Apple OS or Linux, the Financial Times quoted staff as saying.
But no mention was made of staff moving to Chrome OS, Google's own operating system that is due to launch in the second half of the year.
The system is based on Linux and will only run on specifically designed hardware.
The motivation for the move is understood to be the hacking of Google's Chinese operations late last year.
At that point, the company reportedly banned staff from installing Windows on desktop computers.
"We're not doing any more Windows," one employee at Google told the Financial Times, "It is a security effort."
Staff now require clearance from the CIO if they insist on installing Windows, one employee was reported as saying.
Another said: "Linux is open source and we feel good about it. Microsoft we don't feel so good about."
Google declined to give details.
It said: "We're always working to improve the efficiency of our business, but we do not comment on specific operational matters."