Markham is a town in York Region, directly north of Toronto, Ontario, Canada. With a 2005 year-end population of about 268 500 (according to signs at town boundaries), it is larger than many Canadian cities. Markham is part of the Greater Toronto Area.

Markham was first surveyed as a township in 1793 by William Berczy (Johann Albrecht Ulrich Moll 1744-1813), first settled in 1794 and incorporated as a town in 1972. Markham is twinned with Nördlingen, Germany.