The purpose of this study is to determine the level of aggressive behavior of the mentally disabled students at Ajloun Governorate from the teachers' point of views. The sample consisted of all (94) mentally disabled students of simple and intermediate level who were enrolled in the special education centers at the first semester of the academic year (2018-2019). Thirty paragraphs scale was constructed and developed as a study tool. The scale consisted of three dimensions of the aggressive behavior: self-directed aggression, aggression directed towards others and aggression directed towards property and objects. The results showed the level of the aggressive behavior of the mentally disabled students at Ajloun Governorate from the teachers' point of view was high. There were statistically significant differences at ([alpha]=0.05) due to the degree of disability in favor of the intermediate level. There were no statistically significant differences at ([alpha]=0.05) due to the gender.