Markham (pronounced /ˈmɑrkəm/; 2006 population 261,573) is a town located in the Regional Municipality of York, Ontario, Canada. It is located in Southern Ontario directly north of Toronto, and is part of Toronto's Census Metropolitan Area. Despite its qualifications regarding population, it has not had the title of city conferred upon it by the province, and retains its legal status as a town. Markham is one of the fastest-growing communities in Canada. Markham is also the largest town in Canada.

Markham is the fourth-most populous municipality in the Greater Toronto Area, after Toronto, Mississauga, and Brampton. It is home to many cultures. It also claims to be Canada's Hi-Tech Capital with a number of key companies in the area, such as IBM, Motorola, Toshiba, Lucent, Sun Microsystems, Apple, AMEX, and home to the head office of graphics card producer ATI (now part of AMD).

Motto: The Mark of Excellence, Canada's High Tech Capital Coordinates: 43°53′N 79°15′W