Neodymium(III) sulfide is a inorganic chemical compound with the formula Nd2S3[2] composed of a two neodymium atoms in the +3 oxidation state and three sulfur atoms in the -2 oxidation state.

At 1650 °C in a vacuum, the γ compound decomposes to form neodymium monosulfide.

[6] Neodymium(III) sulfide has a high melting point and a lot of polymorphic forms which make it difficult to grow.

[2] When heated, neodymium sulfide can lose sulfur atoms and can form a range of compositions between Nd2S3 and Nd3S4.

Neodymium(III) sulfide is an electrical insulator.