This study investigated the effect of nanoclay (NC) additives on the mechanical performance of high modulus asphalt mixtures (EME). The research studied NC at four different binder weight percentages (0 %, 2 %, 4 %, 6 %) through Marshall stability tests and indirect tensile strength (ITS) and resilient modulus (M_R) evaluations at 5 °C, 25 °C and 40 °C. The results showed substantial improvements across all performance indicators. The Marshall stability increased by 20.7 % when NC reached 6% but flow values decreased by 18.2 % for NC values between 4 % and 6 % because of enhanced permanent deformation resistance. The ITS values showed a 16.5 % increase which demonstrated better tensile strength performance. The M_R values showed significant growth at all test temperatures which reached 55 % at 5 °C and 66.7 % at 25 °C and 64.6 % at 40 °C. The material demonstrated better elastic recovery through these tests, which were conducted at different thermal conditions. The mixture containing 6 % NC reached a richness modulus (K) value exceeding 3.4, which fulfilled the EME2 classification requirements. Statistical analysis (ANOVA) and mechanical evaluation identified 4% NC as the optimal dosage, as it achieved the maximum Marshall stiffness (6.18 kN/mm), while further increases to 6 % did not yield statistically significant improvements. The research shows nanoclay acts as an effective modifier that enhances both structural and mechanical properties of EME mixtures.