Neptunium tetrachloride is a binary inorganic compound of neptunium metal and chlorine with the chemical formula NpCl4.

[1][2] The compound can be prepared by: Other reactions are also used.

[5] NpCl4 crystallizes in tetragonal crystal system of space group I4/amd.

[6] The compound reacts with ammonia to produce neptunium trichloride:[3] Neptunium tetrachloride can be reduced to neptunium trichloride by hydrogen at 450 °C.