The present study aims at identifying the in-service training needs of Grades 5-12 EFL Teachers, as perceived by the teachers, their supervisors and teacher trainers. Moreover, it aims at examining the difference in teachers' perceptions of their needs with respect to gender, nationality, qualification and teaching experience. Three hundred and thirty eight Grades 5-12 teachers participated in the study. This sample represents eight regions which are Batinah North, Batinah South, Dhahira South, Muscat, Al-Dakhaliah, Sharquiah North and Sharquiah South. Moreover, the sample involves eighty EFL supervisors and seventeen teacher trainers. The subject completed a questionnaire which has three parts. The first part elicited information about the respondents' gender, nationality, qualification and working experience. The second part contained a list of 63 in-service education and training needs and the third part has two open questions.' - The main findings of the study were: - 1. Teachers' most important needs are in the area of teaching writing, 2. The study examined the effect of four background factors on teachers' perceptions and revealed that: a. There were no significant differences between male and female teachers in their perceptions of their needs. Grades 5-12 EFL teachers had moderate in-service education and training needs. b. There were significant differences between Omani and non-Omani teachers in their perceptions of their needs. Omani teachers perceived greater need for in-service education and training. c. There were significant differences among teachers with different qualifications. Diploma holders had higher needs for in-service training. d. There were significant differences in teachers' perceptions of in-service education and training needs based on teaching experience. New teachers (1-5 years of teaching experience) perceived greater need for in-service education and training. • In light of the findings of the study, the researcher gave some recommendations and suggestions for further research.