Single‐ and few‐layered InSe flakes are produced by the liquid‐phase exfoliation of β‐InSe single crystals in 2‐propanol, obtaining stable dispersions with a concentration as high as 0.11 g L−1. Ultracentrifugation is used to tune the morphology, i.e., the lateral size and thickness of the as‐produced InSe flakes. It is demonstrated that the obtained InSe flakes have maximum lateral sizes ranging from 30 nm to a few micrometers, and thicknesses ranging from 1 to 20 nm, with a maximum population centered at ≈5 nm, corresponding to 4 Se–In–In–Se quaternary layers. It is also shown that no formation of further InSe‐based compounds (such as In2Se3) or oxides occurs during the exfoliation process. The potential of these exfoliated‐InSe few‐layer flakes as a catalyst for the hydrogen evolution reaction (HER) is tested in hybrid single‐walled carbon nanotubes/InSe heterostructures. The dependence of the InSe …