Abstract: Background and Objectives: A combined effect of aluminium toxicity, drought and net blotch severity stands out to be a major bottleneck hindering the realization of potential yields by the newly released barley varieties in Kenya. However, the relationship among the 3 remains unstudied and undocumented. The study aimed at determining the pre-exposure effect of aluminium toxicity and water deficiency on barley to the severity levels of net blotch foliar disease. Materials and Methods: Twenty four trait-specific barley were planted in a split-plot arrangement in a completely randomized design with 3 replications. The main plots were 20 and 80% field capacities and 148 μM Al while the 12 winters and 12 spring adapted genotypes planted separately represented the sub-plots. Drought and aluminium toxicity stresses were introduced immediately after seedling emergence. Sub-plot inoculation with Pyrenophora teres isolates was done at Zadoks growth stage 15 using 5×103 conidia mL1. Severity assessment was based on a 0-7 severity scale and the data were subjected to multivariate and meta-analysis on Genstat statistical package version 16.0. Results: Initial exposure to abiotic stress led to the expression of low severity levels in all barley genotypes but this varied from one genotype to another informed cluster. Genotype x environment interactions had a significant influence on severity levels and genotype stability as displayed by the rankings, comparisons and which-won-where polygon views of the GGE biplots. Conclusion: In conclusion, initial exposure to aluminium toxicity and water deficiency-induced significant tolerance to net blotch disease in barley irrespective of their genetic constitution and the genotype x environment interaction played a significant role in severity levels and symptom expression.