In computing, an address space defines a range of discrete addresses, each of which may correspond to a network host, peripheral device, disk sector, a memory cell or other logical or physical entity.

Address spaces are created by combining enough uniquely identified qualifiers to make an address unambiguous (within a particular address space). For a person's physical address, the address space would be a combination of locations, such as a neighborhood, town, city, or country. Components^{[clarification needed]} of an address space may be the same but unless all are identical, the locations will be different. An example could be that there are multiple buildings at the same address of "32 Main Street" but in different towns demonstrates that different towns have different, although similarly arranged, street address spaces.

An address space usually provides (or allows) a partitioning to several regions according to mathematical structure it has. In the case of total order, as for memory addresses, these are simply chunks. Some nested domains hierarchy appears in the case of directed ordered tree as for the Domain Name System or a directory structure; this similar to hierarchical design of postal addresses. In the Internet, for example, the Internet Assigned Numbers Authority (IANA) allocates ranges of IP addresses to various registries in order to enable them to each manage their parts of the global Internet address space.