Don Mills is a mixed-use neighbourhood in Toronto, Ontario, Canada. It was developed in the 1950s and 1960s to be a self-supporting "new town" and was at the time located outside Toronto proper in the suburb of North York. Consisting of residential, commercial and industrial sub-districts, it was planned and developed by private enterprise.

In several ways it became the blueprint for postwar suburban development in Toronto and contemporary residential neighbourhoods. It is bounded by York Mills Road to the north, Canadian Pacific Railway to the south, Leslie Street to the west, and Don Valley Parkway to the east. It is part of federal and provincial electoral district Don Valley East, and Toronto electoral ward 16: Don Valley East.

The Don Mills area was first settled by Europeans in 1817. The area was a considerable distance from the town of York, but the Don River provided an easy means of transportation, and also a source of power for a number of mills along its length.

While the city of Toronto steadily expanded, the Don Mills area remained rural until after the Second World War. It was cut off from the city by ravines to the south, east, and west. Only two roads connected to the area: York Mills Road and Don Mills Road. In 1950 the area consisted of about 20 farms.

Don Mills was designed as a model community between 1952 and 1965. Land use, architectural design and building materials were carefully regulated. Many aspects of its design have been imitated in suburban developments across Canada. Its planners would give people priority over industry and cars.

This combination of emptiness and proximity to the city attracted the attention of industrialist E.P. Taylor. His original plan was to erect a brewery on the site, along with a small community to house the workers. Taylor had limited previous experience in the property development business, but had built a project named the Wrentham Estates in York Mills. Seeing the profit to be made with such projects, Taylor abandoned the brewery idea and decided to simply build a new town on the 2,000 acres (8.1 km²) he had acquired.

In 1951, he began planning the Yorktown community (as it was first known), and it was announced on March 11, 1953. The community was to be built on about 8.35 km² (3.22 sq mi) of farmland centred at the intersection of Don Mills Road and Lawrence Avenue East, with an expected cost of $200 million. Development was headed by the Taylor-owned Don Mills Development Company, (known as O'Keefe Realty in the days of the brewery development).

The design of Don Mills was influenced by Ebenezer Howard's Garden City, and by the principles of two American town planners, Clarence Stein and Henry Wright, who developed the garden city community of Radburn, New Jersey. Design of the project was entrusted to Macklin Hancock, the son-in-law of Taylor's executive assistant. Still in his mid-20s, Hancock was a graduate student at Harvard when approached for the job. At Harvard Hancock had studied under a number of the founders of modernism and new town planning including Walter Gropius, William Holford, and Hideo Sasaki.