abstract i the purpose of this study was to launch a thorough investigation concerning the possibility of differing orientations to the writing proficiency construct by native and non-native english speaking teacher raters. it mainly revolved around the international english language testing system (ielts) that is widely administered and employed as a measure of general proficiency in english. while in iran the performance on this test is regularly assessed by trained non-native english speaking (nnes) raters, the question has arisen as to whether the standards they apply in judging writing performance are comparable to those of native english speakers (nes). to answer this question, the researcher compared the samples scored by 40 nes raters (20 males+ 20 females) with the same 40 samples that were rated by nnes raters, 20 males (10 experienced + 10 inexperienced) + 20 females (10 experienced + 10 inexperienced) on the basis of 4 rating criteria, namely task response (tr), coherence and cohesion (cc), lexical resources (lr) and grammatical range and accuracy (gra). the results demonstrated that with regard to lr and gra male experienced nnes raters were significantly different from their counterparts in nes group. female experienced nnes raters were also significantly different from female nes raters on the basis of lr, cc, lr and gra. male nes raters were also significantly different from experienced female nes raters with regard to lr criterion. the experienced nnes males overall were closer to nes raters and experienced female nnes raters had the biggest difference. in this study it was also discovered that concerning cc, gra, and holistic scores male and female nnes raters were significantly different based on the factor of experience while the same difference was not found to be significant on the basis of tr and lr. it was also revealed that gender did not play any significant role between male and female nnes raters with regard to tr, cc, lr, gra, and holistic scores. key words: writing task, ielts, native and non-native raters and inter-rater variability