Despite the importance of teacher professional development, it has not been systematically investigated in the Ministry of Defence context. The present study aims at identifying the professional development needs of MOD EFL teachers as perceived by the teachers themselves. It also aims at exploring the facilitating and constraining factors that influence their professional development. The instruments designed for the purpose of this study were semi-structured interviews and a questionnaire. The questionnaire consisted of three main dimensions including MOD EFL teachers' current involvement in professional development activities, their preferences of professional development activities and facilitating and constraining factors that influence their professional development. The population of the study consisted of all MOD EFL teachers. The sample of the study consisted of 100% of the population (74 teachers). The sample consisted of native and non-native speaking teachers. These teachers teach different syllabuses (general English and ESP). The teaching experience of the sample ranged from 1 year to more than 20 years. The main findings of the study were: 1. MOD EFL teachers' involvement in top-down professional development activities is higher than their involvement in bottom-up ones. 2. Their involvement in top-down activities was of moderate frequency and of low frequency in bottom-up ones. 3. They prefer face-to-face professional development programs to on-line ones. 4. The study examined the influence of three background factors on teachers involvement and preferences and revealed that: 4.1 There are statistically significant differences between native and non-native speaking teachers in their involvement in top-down activities in favor of non-native speaking teachers. 4.2 There are statistically significant differences in teachers' involvement in top down activities based on experience in favor of novice teachers. 4.3 There are no statistically significant differences in teachers' involvement in both top-down and bottom-up activities based on syllabus. In the light of the findings of the study, the researcher presented some recommendations for MOD educational administrators, professional development programs' designers and MOD EFL teachers. The researcher also gave some recommendations for further research.