Zinc (Zn) deficiency is a global micronutrient problem in agricultural systems. The main target of this experiment was to investigate the effectiveness of foliar application of Zn under field conditions. Grain yield and Zn concentration in seed were assessed with three replicate plots per treatment in a factorial (2 x 3 x 2) experiment for two barley cultivars (Yusuf and Julgeh), three foliar ZnO applications (nano,ordinary and nano+ordinary ZnO) and two commercial inocula of arbuscular mycorrhizal (AM) fungi (F. mosseae and R. irregularis). Among all Zn foliar applications, Zn applied in both nano and nano+ordinary forms were labile and resulted in the highest Zn concentration in grain of both barley cultivars. Cultivar Julgeh had higher grain Zn concentrations than did cultivar Yusuf in the same treatments. Nano ZnO was more effective than the ordinary form of ZnO and had the highest potential to improve physiological traits,plant growth and yield parameters in both cultivars. There was also a positive impact of the nano form of ZnO on phytase activity andcarbonic anhydrase concentration in both barley cultivars. Inoculation with commercial inocula of AM fungi also enhanced grain Znconcentration, with Julgeh more responsive to inoculation with F. mosseae, and Yusuf more responsive to inoculation with R. irregularis. Generally, the combined application of Zn and inoculation with AM fungi improved physiological traits, grain yield and Zn availability to these two barley cultivars grown under field conditions. Accordingly, the nano form of Zn positively enhanced shoot morphological parameters, physiological parameters and grain Zn concentration. Application of the nano form ZnO in combination with inoculation with AM fungi had the most beneficial effects on grain Zn concentration, so this combined practice may have potential to reduce the requirement for application of synthetic Zn chemical fertilizers.