Boron can cause growth deficiency and yield loss in plants at both low and high concentrations. Turkey holds 72,5% of known world boron reserves, and boron toxicity causes major agricultural problems. In a search to identify resistant species, Puccinellia distans (weeping alkaligrass), growing near boron mining sites in Turkey, was found to tolerate toxic boron concentrations. This species has been studied at the level of gene transcription, however, investigation at the protein level has not yet been performed. In this work, the boron stress tolerance mechanism of P. distans was investigated with proteomic approaches. For this purpose, plants were divided into control and stress groups with optimal and toxic boron concentrations, respectively. Boron accumulation was observed in leaf tissues at the end of growing stages. Leaf and root tissues were checked for tissue boron concentrations at the end of their growth period with ICP-MS. Both leaves and roots were found to accumulate around 6 g B/kg dry tissue. Total proteins were extracted from leaf tissues of both groups and analyzed in LC-MS instrument to determine the differences between protein profiles. One hundred and nine significantly differentially expressed proteins were identified in this work. Three upregulated proteins were selected as candidate proteins for boron hyperaccumulation tolerance. This work proved successful in identification of some of the proteins responsible for boron hyperaccumulation in P.distans and paving the way for future studies to use P. distans for phytoremediation in areas with excess boron.