In the field of silicon photonics, previous studies have shown that ordered multilayered structures of gallium arsenide have interesting and advantageous properties. These GaAs semiconductor devices are employed in promising applications for photonic devices like quantum dot lasers. Other applications include the development of optoelectronic devices that have an improved performance in high-speed telecommunications and information processing. However, there has not been direct experimental evaluation on the effect of threading dislocations on the thermal conductivity of GaAs devices. It is important that this analysis is done to better understand how the heat dissipation affects the efficiency of the photonic devices and their lifetime cycle. In this work, we execute a noncontact laser-induced transient thermal grating (TTG) technique to investigate properties like thermal diffusivity and thermal conductivity of GaAs-based buffers on Si. We studied samples with different threading dislocation densities (TDD) which were generated during the growth process. Samples with a higher TDD are expected to have a lower thermal conductivity than the samples with lower TDD due to increased phonon scattering. These results indicate the importance of growing GaAs with a significant reduction of TDD through rational design of devices structures, to obtain high thermal conductivity and improve heat dissipation.