In arid and semi-arid regions, the use of saline irrigation water in landscape systems is becoming increasingly unavoidable, yet salinity adversely affects turfgrass growth and visual quality. Glycine betaine (GB), a compatible solute, has been proposed as a potential osmoprotectant to mitigate salt-induced stress. This study evaluated the responses of four cool-season turfgrass species (Festuca rubra subsp. rubra, Lolium perenne, Festuca arundinacea, and Poa pratensis) to foliar-applied GB under non-saline and saline (6 dS m-1) conditions in a controlled greenhouse experiment. Salinity negatively influenced turf quality, turf color, chlorophyll content, and biomass parameters; however, the magnitude of these effects varied significantly among species. Significant species & times; salinity and species & times; GB interactions indicated that plant responses to both salt stress and GB application were strongly species-dependent. F. arundinacea and P. pratensis exhibited comparatively greater stability in growth and visual quality under salinity, whereas L. perenne showed higher sensitivity. Although GB did not exert a consistent main effect across all parameters, it partially mitigated salinity-induced reductions in specific species and treatment combinations. These findings highlight that turfgrass tolerance to salinity and the effectiveness of GB application are governed primarily by genotype-dependent responses rather than uniform treatment effects. The results underscore the importance of species selection as a primary strategy for saline turf management, with GB serving as a potentially supportive but species-specific intervention.