Germanium diselenide is an inorganic compound, with the chemical formula of GeSe<sub>2</sub>.
Germanium diselenide is prepared by reacting stoichiometric amounts of germanium and selenium or by reacting germanium tetrachloride with hydrogen selenide:
Germanium diselenide reacts with selenium and hydrazine to obtained yellow (N<sub>2</sub>H<sub>5</sub>)<sub>4</sub>Ge<sub>2</sub>Se<sub>6</sub>, a selenidogermanate.
It reacts with lead selenide and gallium(III) selenide at high temperatures to obtain PbGa<sub>2</sub>GeSe<sub>6</sub>.