abstract the following study, in the first place, attempted to examine the effect of less experienced teachers participation in experienced teachers classes on their own skills and teaching methodology, in the second place, attempted to find out the role of teachers training in students achievements. for this purpose, 21 efl teachers were selected according to available sampling in kish language school in bojnurd, a city in the northeast of iran. also 169 male and female students taking elementary and pre-intermediate courses formed the participants of this quasi-experimental study. the participants were assigned into experimental and control group. four instruments were employed to collect data: a sample of toefl test, ket and pet tests, and interview. data analysis and statistical calculations through ttest and one way anova revealed that although both control and experimental group students proficiency enhanced, there was a significant difference in experimental group students scores before and after treatment. furthermore, the result of interview showed that almost all teachers were satisfied with their participation in experienced teachers classes. the conclusions and implications of the research are further discussed with reference to earlier findings.