Missing middle housing is a concept that describes a range of housing forms that have multiple units, constructed in the general scale and form of houses. As such, they fit the built form of neighbourhoods with single-family homes.

Missing middle housing is also intended to create walkable, sustainable neighbourhoods.

• Apartment: a building with 5 or more units, all accessed through a shared entrance from the street.
• Accessory Apartments: A self contained secondary residential unit that is located on the same lot as a primary dwelling. They can be found within, attached to, or detached from the primary dwelling.
• Duplex: 2 units, one on top of the other, each with its own private entrance.
• Triplex: 3 units, stacked on separate floors, each with its own entrance.
• Fourplex: 4 units in one building. Units can be side-by-side or stacked. Each has a separate entrance.
• Townhome: A group of three or more attached single unit dwelling houses that are divided vertically beside each other, with each dwelling unit having its own independent entrance directly from the outside.
• Semi-Detached: 2 side-by-side homes sharing one wall. Each has a private entrance, either from the street or a shared space.
• Stacked Townhouse: A building, four storeys or less, where the dwelling units are located entirely or partially above the other portion of the dwelling units, and where each dwelling unit has its own independent entrance to the exterior.
• Low Rise Apartment: A building that is four storeys or less with more than four dwelling units, all accessed through a share entrance from the street.