Aluminium antimonide (AlSb) is a semiconductor of the group III-V family containing aluminium and antimony. The lattice constant is 0.61 nm. The indirect bandgap is approximately 1.6 eV at 300 K, whereas the direct band gap is 2.22 eV.

Its electron mobility is 200 cm²·V·s and hole mobility 400 cm²·V·s at 300 K. Its refractive index is 3.3 at a wavelength of 2 µm, and its dielectric constant is 10.9 at microwave frequencies.