David Lennox Mills was an American computer engineer and professor emeritus at the University of Delaware. He was an Internet pioneer who led the Gateway Algorithms and Data Structures (GADS) Task Force. He was known as the internet's "Father Time" for designing the Network Time Protocol, which is intended to synchronize all participating computers across different computer systems and networks to within a few milliseconds of Coordinated Universal Time.

The Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks. In operation since before 1985, NTP is one of the oldest Internet protocols in current use. NTP was designed by David L. Mills of the University of Delaware.