This study aimed at investigating the effect of a training program based on OER on the professional development of AlDakhlia Governorate teachers. The study also investigated the teachers' attitudes towards this form of training using an experimental research method. The training program was prepared as an interactive lecture presentation for 3 days of training; one session per day for 2 hours. The educational content was available on the SHMS platform and then the experiment was implemented on 40 teachers, where 20 teachers were in the experimental group and the other 20 teachers were in the control group with professional years of experience ranged between 5 and 10 years. The results showed the significant role of the OER platforms in teachers' professional development in the form of an increase e in the level of knowledge and teaching skills. Also, the participated teachers' positive attitudes towards the online professional development indicated that these OER environments are rich in knowledge and cooperative activities. Generally speaking, these OER platforms encourage teachers to keep up with their professional development and self-learning throughout their career life.