Kleinburg is an unincorporated village in the city of Vaughan, Ontario, Canada. It is home to the McMichael Canadian Art Collection, an art gallery with a focus on the Group of Seven, and the Kortright Centre for Conservation. In 2001, the village and its surrounding communities had a population of 4,595; the village itself has 282 dwellings, with a population of 952. Kleinburg comprises a narrow section of hilly landscape situated between two branches of the Humber River. The historic village is bounded by Highway 27 on the west and Stegman’s Mill Road to the east. Kleinburg has subsumed the nearby hamlet of Nashville, but it has not itself been fully subsumed into the main urban area of Vaughan.

The village is located between two branches of the Humber River, and features dense forests throughout its 1.05 km² of land area. Its northern and western peripheries are primarily agricultural.

The community began in 1848 when John Nicholas Klein (1825–1854), a German-Canadian settler built a flour mill along the Humber River's west branch in the valley in 1847. A settlement soon resulted at the bottom of the hill, originally named "Kleinsburg" (after John Klein, and "berg" being German for hilly country or hill). The village at the top of the hill was known as "Mount Vernon", but by 1890 both became known as Kleinburg (sometimes shown as Klineburg). The Howland family later took over the flour mill, and added a sawmill and store. Over time, more and more businesses sprung up to support the mills, notably the Howland's flour mill, which was the largest between Barrie and Toronto and attracted farmers for miles. A community developed in town, with hotels, merchant shops, schools and churches.

A plank road was built through Kleinburg in 1860 by the Vaughan Plank Road Company, running from Thistletown north through Woodbridge, Pine Grove, and Kleinburg to the King township border. The road had tollbooths (including one located in Kleinburg), and travelers were made to pay a toll for the upkeep. There was local opposition from farmers in later years, and the municipality took over in 1896, eliminating the tolls.

Due to the sprawling valleys and topography of the area, a railway station for Kleinburg had to be established outside of town on the Toronto, Grey & Bruce Railway line (present-day Canadian Pacific Railway) in 1870, to the west of town on the other side of the Humber River valley. This area became the community known as Nashville (after a local named Jonathan Scott and his wife who came from Nashville, Tennessee. A hotel, grain elevator, church, coal and lumber yard sprung up. A Nashville post office was established in 1881.

The first Kleinburg railway station was built by the TG&B in 1870, but a new station was built in 1907 by the Canadian Pacific due to line upgrades. Passenger service to the Kleinburg railway station ended in 1964, but the station was saved due to efforts by prominent Canadian and Kleinburg resident Pierre Berton for use by Scouts Canada. In 1976 it was moved into town for preservation, next to the Kleinburg Public School.

Highway 27 was built to the west of town along the Humber River valley in 1937-1938, diverting highway traffic from travelling through the town proper on Islington Avenue.

In the 1960's, some suburban residential areas began to develop at the south end of the small town.