House numbering is the system of giving a unique number to each building in a street or area, with the intention of making it easier to locate a particular building. The house number is often part of a postal address. Note that the term "house number" refers to the number on the building even if the building is not a house but is a commercial structure or even a vacant lot with a mailbox.

House numbering schemes vary by place, and in many cases even within cities. In some areas of the world, including many remote areas, houses are not numbered at all, instead simply being named.