In computer networking, broadcasting refers to transmiting a packet that will be received (conceptionally) by every device on the network. In practice, the scope of the broadcast is limited to a broadcast domain. Contrast unicasting and multicasting.

Not all computer networks support broadcasting; for example, neither X.25 nor frame relay supply a broadcast capability, nor is there any form of Internet-wide broadcast. Broadcasting is largely confined to local area network (LAN) technologies, most notably Ethernet and Token Ring, where the performance impact of broadcasting is not as large as it would be in a wide area network.

Both Ethernet and IPv4 use an all-ones broadcast address to indicate a broadcast packet. Token Ring uses a special value in the IEEE 802.2 control field.

Due to its "shotgun" approach to data distribution, broadcasting is being increasingly supplanted by multicasting. For example, IPv6 supports neither directed broadcasts nor local broadcasts.