Robert Gray Gallager (born May 29, 1931) is an American electrical engineer known for his work on information theory and communications networks.

Gallager was elected a member of the National Academy of Engineering (NAE) in 1979 for contributions to coding and communications theory and practice.

[2] For most of his career he was a professor of electrical engineering and computer science at the Massachusetts Institute of Technology.

His work (along with fellow-MIT faculty member Dave Forney) on quadrature amplitude modulation led to the 9600 bit/s modems that provided Codex's commercial success.

In 1978, he showed, with graduate student Roger Camrass, that packet switching was optimal in the Huffman coding sense.

[8][9] He published a book Data Networks in 1988, with a second edition 1992, co-authored with Dimitri Bertsekas, which helped provide a conceptual foundation for this field.

In 1999 he received the Harvey Prize from the American Society for the Technion – Israel Institute of Technology.

Gallager was President of the IEEE Information Theory Society in 1971, a member of its board of governors from 1965 to 1972 and again from 1979 to 1988.