Microsoft XP may refer to:
Windows XP editions, especially: Windows XP Home and Professional Editions Windows XP 64-Bit Edition (For Itanium processors) Windows XP x64 Edition (For x86-64 processors) Windows Server 2003, a product from the Windows XP era for server applications Windows Fundamentals for Legacy PCs, a stripped-down version of Windows XP Microsoft Office XP, released prior to Windows XP, even though XP is better known to refer to the Windows OS
See also AMD Athlon XP, a microprocessor marketed for Windows XP to run on, hence the name.