John M. McQuillan (born 1949) is an American computer scientist, known for studies of adaptive routing in the early ARPANET.
He received his A.B. (1970), M.S. (1971) and Ph.D. (1974) in applied mathematics from Harvard University. He was at the same time (since 1971) employed at the equipment manufacturer Bolt, Beranek and Newman in Cambridge, MA, where he programmed the Interface Message Processor, work that in part led to his dissertation Adaptive routing for distributed computer networks advised by Jeffrey P. Buzen (1974), in which McQuillan developed ways to reroute messages around faulty and congested areas in the Internet based on delay feedback. These mechanisms were used in the first link-state routing protocols (1978).
He also edited the two early introductions to networking, Understanding the new local network technologies (BBN, 1978) and A practical view of computer communications protocols (IEEE, 1978).
He started McQuillan Consulting in Concord, MA (1982), became a columnist to Business Communications Review as well as an annual organizer of the Next Generation Network (NGN) conferences. He became partner in International Venture Partner (1996). Today, he is the director of McQuillan Ventures, that invests in network infrastructure companies.