A(1-x)In(x)As(1-y)Sb(y) epilayers and Al1-xInxAs1-ySby/GaSb multilayers (0.5 less than or equal to y less than or equal to 1.0) have been grown by molecular beam epitaxy on GaSb (100) substrates as part of an investigation for potential use of this material＇s system as kinetic heterojunctions (KHJs). Viable KHJ＇s require lattice matching and a zero-conduction-band offset to GaSb, necessitating a high degree of compositional control. Therefore, a detailed study of the growth of Al1-xInxAs1-ySby epilayers has been conducted. Synthesis of the arsenide/antimonide quaternary system is problematic due to the miscibility gap throughout the composition range, therefore, the compositional dependence on the Sb:As flux, Sb:In flux, and substrate temperature has been studied. In situ reflection high-energy electron diffraction was used to monitor the surface reconstruction during growth.Crystalline quality and composition of single layer and multilayer samples have been determined by double-crystal x-ray diffraction and electron dispersion spectroscopy. Hall-effect measurements were performed to determine layer mobility and conductivity.