In this work, the effect of Polyethylene glycol (PEG) polymers with different molecular weight (Mw=400, 1500 and 4000 g/mol) was investigated to explore their relative effectiveness in inhibiting crystal growth of barium sulfate (BaSO4, barite). Langmuir and Temkin isotherm were utilized to evaluate the adsorption behaviour of PEG polymers on the barite crystals. It was foun that PEG polymers tested in this study are effective as growth inhibitors under the experimental conditions.