n-Hexyllithium, C₆H₁₃Li, sometimes abbreviated to HxLi or NHL, is an organolithium compound used in organic synthesis as a strong base or as a lithiation reagent. It is usually encountered as a colorless or pale yellow solution in hexanes. Such solutions are highly sensitive to air and can ignite when treated with water.

In terms of chemical properties, hexyllithium and n-butyllithium (BuLi) are very similar. As a base, hexyllithium generates n-hexane as a byproduct rather than gaseous butane, which results from the use of BuLi. Another advantage for HxLi is that it is slightly less reactive.^[2] Both of these aspects encourage industrial applications. It is commercially available as a solution in mixed hexanes, usually at a concentration of about 2 M for laboratory use or 33% for industrial use.

As for BuLi, the structure and formula for HxLi are often depicted as a monomer. Like all organolithium compounds, it exists as clusters in solution and as a solid.^[3]