A detailed study of interface states in interfacial misfit (IMF) grown GaSb on GaAs substrates is presented. Two types of structures, namely, uncompensated and Te compensated, are investigated using current–voltage, capacitance–frequency, conductance–frequency, and deep level transient spectroscopy techniques. Our studies reveal that incorporation of Te at the interface (IMF) causes a degradation of the Te-compensated devices. A higher number of electrical active defects and higher value of interface states are detected in Te-compensated IMF GaSb/GaAs devices compared with as-grown IMF GaSb/GaAs devices.