A Digital Subscriber Line (DSL) modem is a device used to connect a computer or router to a telephone circuit that has Digital Subscriber Line service configured. Like other modems, it is a type of transceiver.

Some DSL modems also manage the connection and sharing of the DSL service in a network, in this case, the unit is termed a DSL router or residential gateway. DSL routers have a component that performs framing, while other components perform Asynchronous Transfer Mode Segmentation and Reassembly, IEEE 802.1D bridging and/or IP routing (including network address translation). Typical user interfaces are Ethernet and Universal Serial Bus (USB). Although a DSL modem working as a bridge does not need an IP address, it may have one assigned for management purposes.