A company that provides Internet access to its customers. The majority of ISPs are too small to purchase access directly from the network access point (NAP), and instead buy pieces of bandwidth that are available from larger ISPs. Access to the Internet can be provided either via modem or by direct connection, which offers far higher speeds.

Internet service providers are different from online services, although these services sometimes also provide access to the Internet. Online services provide access to exclusive content, databases and online discussion forums that are not available outside the service.