The 1979 Gray International Open, also known as the Cleveland Grand Prix, was a men's tennis tournament held on outdoor hard courts at the Harold T. Clark Tennis Stadium in Cleveland, Ohio in the United States that was part of the 1979 Grand Prix circuit.

It was the fifth edition of the tournament and was held from August 13 through August 19, 1979.

[a] Second-seeded Stan Smith won the singles title and earned $10,000 first-prize money.

[4][5] Stan Smith defeated Ilie Năstase 6–3, 6–4 Stan Smith / Robert Lutz defeated Francisco González / Fred McNair 6–3, 6–4