The effect of freeze-thaw cycles on the hydraulic conductivity of a geosynthetic clay liner (GCL) is assessed with respect to Jet Fuel A-1 (Arctic diesel). GCL specimens subjected to 0 and 5 freeze-thaw cycles and specimens recovered from a site on Brevoort Island in the Canadian Arctic after 3 years are examined. The GCL recovered from Brevoort Island had the lowest hydraulic conductivity with respect to de-aired water. Freeze-thaw cycles did not have a negative impact on hydraulic conductivity with respect to de-aired water. Freeze-thaw cycles did increase the hydraulic conductivity, k, with respect to Jet Fuel A-1. However, the hydraulic conductivity was still very low and the results suggest that the GCL can be expected to perform well as a hydraulic barrier in the medium term with respect to the effects of both freeze-thaw and permeation with Jet A-1. More testing is needed to assess long term performance.