An experimental and statistical investigation is carried out to analyze the influences of three variables (limestone powder, glass powder, and alkali content) on performance of alkali activated slag mortar. Response surface methodology (RSM) was used to model all measured responses like 28‐day flexural and compressive strength, water absorption, and dry shrinkage. Analysis of variance showed that all developed models were statistically significant. The interaction between the corresponding variables was analyzed using three‐dimensional response surface plots that were drawn using developed regression models. Optimization was performed using desirability approach of the RSM with an objective to maximize 28‐day flexural and compressive strength while minimizing water absorption and drying shrinkage. The optimum values of limestone powder, glass powder, and alkali content with highest desirability of 0.706 are 15.80, 17.02, and 6.71%, respectively. The predicted combination was validated by confirmatory tests and the error in prediction was found to be within 3.5%.