Background & Objective: Deaf students are one of the groups of children with special needs, and deafness is widely recognized as one of the most common disabilities. Deafness is a generic term referring to all types, causes, and degrees of hearing loss. To delineate the impact of a hearing loss on the development of speech, language, and literacy, a number of descriptive variables have been identified, including degree of hearing impairment; age at onset; age at identification; etiology; presence of additional disabilities; and hearing status, level of involvement, communication mode, socioeconomic status of the parents or caregivers. Research suggests that deaf students are more isolation by their peers than are other children. In social situations, it often does not take long for deaf students to be ostracized. Unfortunately, the negative academic status experienced by deaf students is difficult to overcome and is usually long-lasting. Adding to their socialization problems and academic problems, many deaf students also have problems in aspects of working memory and social COMPETENCY. The enduring nature of deafness easily leads to social isolation. The result is that many deaf children and adults have few friends. This can set up a vicious circle in which they attempt to win friends by latching onto the least chance for interaction with others. These problems can be reducing their social COMPETENCY. In the word of the other, it considered that deaf students have severe problems in aspects of working memory and social COMPETENCY compared to hearing students. So, the purpose of the present study was to investigate the compare working memory and social COMPETENCY in hearing and deaf students. Methods: The present research was a causal-comparative study. The statistical population consisted of deaf and hearing girl students aged 10 to 13 years in Gorgan city in 2017-2018 Academic years. Deaf and hearing girl students selected by convenient sampling method. Each group consists of 40 individuals. The instruments of this research were working memory test (Daneman and Carpenter, 1980) and social COMPETENCY questionnaire (Felner, lease, and Phillips, 1990). The obtained data were analyzed by using Kolmogorov Smirnov test, M. Box test, Leven test, independent t-test and multivariate analysis of variance test with the 23rd version of SPSS (P<0. 05). Results: At first, the normality of variables and contingency of variance assumptions tested. The Kolmogorov Smirnov test showed that all variables were normal (P>0. 05). Also, Leven test confirmed contingency of variances assumption. So, assumptions of MANOVA test confirmed and can be used the MANOVA test for analysis of data. The results showed that scores mean and standard deviation of working memory in deaf students (62. 46± 3. 27) was significantly (p≤ 0. 05) lower than hearing students (73. 85± 3. 11). Also, deaf students were significantly (p<0. 05) lower than hearing students in cognitive skills (15. 76± 1. 63 versus 10. 31± 1. 87), behavioral skills (151. 28± 5. 28 versus 126. 09± 5. 74), emotional COMPETENCY (14. 93± 1. 47 versus 9. 78± 1. 40) and motivational sets (31. 19± 2. 38 versus 25. 34± 2. 12). Conclusion: According to the finding of the research, working memory and social COMPETENCY in deaf students were lower than the hearing students. Thus, a special rehabilitation program in these areas to increase the working memory and social COMPETENCY of deaf students.