A wireless network interface controller (WNIC) is a network interface controller which connects to a wireless network, such as Wi-Fi, Bluetooth, or LTE (4G) or 5G rather than a wired network, such as an Ethernet network. It consists of a modem, an automated radio transmitter and receiver which operate in the background, exchanging digital data in the form of data packets with other wireless devices or wireless routers using radio waves radiated by an antenna, linking the devices together transparently in a computer network. A WNIC, just like other network interface controllers (NICs), works on the layers 1 and 2 of the OSI model.

A wireless network interface controller may be implemented as an expansion card and connected using PCI bus or PCIe bus, or connected via USB, PC Card, ExpressCard, Mini PCIe or M.2.

The low cost and ubiquity of the Wi-Fi standard means that many newer mobile computers have a wireless network interface built into the motherboard.

The term is usually applied to adapters using the Wi-Fi (IEEE 802.11) network protocol; it may also apply to a NIC using protocols other than 802.11, such as one implementing Bluetooth connections.

An 802.11 WNIC can operate in two modes known as infrastructure mode and ad hoc mode:

The IEEE 802.11 standard sets out low-level specifications for how all 802.11 wireless networks operate. Earlier 802.11 interface controllers are usually only compatible with earlier variants of the standard, while newer cards support both current and old standards.

Specifications commonly used in marketing materials for WNICs include:

Most WNICs support one or more of 802.11, Bluetooth and 3GPP (2G, 3G, 4G, 5G) network standards.