James "Jim" Edward Allchin (born in Grand Rapids, Michigan in 1951) is a former executive at Microsoft, where he was responsible for many of the platform components from Microsoft including Microsoft Windows, Windows Server, server products such as SQL Server, and developer technologies. He may be most known for building Microsoft's server business. After sixteen years at Microsoft, Allchin retired in early 2007 - on the day that Microsoft officially released the Windows Vista operating system to consumers. He is also known for his leading role in the architecture and development of the directory services technology Banyan VINES. He has won numerous awards through the years such as Technical Excellence Person of Year in 2001.

Allchin was born to a poor family in Grand Rapids, Michigan, in 1951. While he was still an infant, the family moved to Keysville, Florida, where his parents worked on a farm. Later Allchin and his older brother Keith also worked on the farm to help the family's finances.

While fixing equipment on the farm, Allchin developed an interest in engineering. He briefly studied electrical engineering at the University of Florida but dropped out to play in a number of bands. However he returned to the university and graduated with a B.S. in Computer Science in 1973.