In this work, the thermal conductivity, enthalpy of fusion, specific heat capacity, and thermal diffusivity of the Al-5.5Zn-2.5Mg (wt.%) ternary alloy have been investigated. Thermal conductivity of as-cast Al-5.5Zn-2.5Mg alloy was measured using comparison cut bar method in the temperature range of 323-723 K. With the increase of temperature, thermal conductivity decreased gradually in as-cast Al-5.5Zn-2.5Mg alloy. The thermal temperature coefficient was calculated from the respective graph. The enthalpy of fusion and the specific heat capacity during the transformation were also determined. Thermal diffusivity changes were calculated as a function of temperature through the obtained thermal data. It was observed that thermal diffusivity values decreased with increasing temperature.