Thiazyl trifluoride is a chemical compound of nitrogen, sulfur, and fluorine, having the formula NSF3.

It exists as a stable, colourless gas, and is an important precursor to other sulfur-nitrogen-fluorine compounds.

[2] It has tetrahedral molecular geometry around the sulfur atom, and is regarded to be a prime example of a compound that has a sulfur-nitrogen triple bond.

[5] Direct fluorination of mercury difluorosulfinimide (Hg(NSF2)2) does not give thiazyl trifluoride, but instead the isomeric fluoriminosulfur difluoride (F2SNF).

[7] However, the fluoride ligands are labile, and can be displaced by secondary amines.