Neptunium(III) chloride or neptunium trichloride is an inorganic compound with a chemical formula NpCl<sub>3</sub>. This salt is strongly radioactive.
Neptunium(III) chloride can be produced by reducing neptunium(IV) chloride by ammonia or hydrogen at 350~400 ðC:
Neptunium(III) chloride hydrolyzes at 450 ðC and forms an oxychloride NpOCl.