Identifying stable, high-yielding genotypes is essential for food security. This is particularly relevant in the current climate change scenario, which results in increasing occurrence of adverse conditions in the Mediterranean region. The objective of this study was to evaluate stability of barley (Hordeum vulgare L.) grain yield, and its relationship to the duration of the growth cycle and its stability under Mediterranean conditions in Egypt. Nineteen genotypes were evaluated during three growing seasons (2013–14 to 2015–16) at two locations (Elkhatara, Ghazala) and two growing seasons (2014–15 and 2015–16) at a third location (Ras-Sudr), i.e. eight environments (location–year combinations) in total. The linear regression explained a significant 48.2% and 22.8% of GEI variation for days to heading and grain yield, respectively, and the genotypic linear slopes were highly related to the first principal component of the AMMI model. Although all genotypes were well adapted to the region, there were different GEI responses, with changes in ranking across locations. Some stable and broadly adapted genotypes were identified, as well as unstable genotypes with specific adaptations. High yields across environments were attained by very stable (G4, G5), intermediate and stable (G1, G9) and highly responsive (G18, G19) genotypes. In general, responsiveness (b values) of yield and days to heading were negatively correlated, and high yielding genotypes showed different patterns of responses of days to heading. Genotypes G1, G4, G5 and G9 seemed best adapted overall, with longer season genotypes (e.g. G18 and G19) offering prospects to explore other formats of varieties in breeding, particularly for situations of climate instability.