Yes, it is totally compatible.

Mozilla Firefox is a very flexible program! You can install the Windows version in all Windows versions from XP to 7.

If this helped you don't forget to hit 'Solved it' Button so the topic will be closed.

The larger question is, does your hardware support Firefox 6.0?

http://www.mozilla.com/en-US/firefox/6.0/system-requirements/

Just to verify CseC's answer ... Firefox 6.0 and 7.0 are compatible with XP SP2 if I meet the hardware requirements?

No, the Firefox 4.0+ versions need ServicePack 3.

@ the-edmeister I saw some people using FF 6.0.1 with Windows XP SP2. Is it really not compatible?

Also one other thing. In system requirements page of FF Ver 6.0 there's nothing showing that in XP, SP3 is needed (Or did I miss anything?) Shouldn't it be added there?

Thank you.