Windows NT 3.51 is an operating system developed by Microsoft. It was released on May 30, 1995, nine months after Windows NT 3.5 and two months before Windows 95. It is part of the Windows NT family and Windows NT 3.5x. It is the final version of Windows 3.x. Windows NT 3.51 was the first version of a short line of Windows NT available for the PowerPC architecture. It is the third Windows NT version.