Orthogonal frequency division multiplexing (OFDM) is a method of digital modulation causing a signal to be split into several narrowband channels at differing frequencies. It was invented between 1960 and 1970, in order to minimise interference between near channels. A similar technology is Frequency-division multiplexing. Digital television and voice broadcasts are two implementations of this technology, which is widely used in Europe.

OFDM is also used in the 802.11a and 802.11b wireless networking standards.