Background and Aim: Due to the high prevalence and worldwide distribution of Enterobius vermicularis and its readily transmission among children, parents' knowledge and health education have an important role in restriction and infection control. This study was performed to evaluate the girl students' knowledge about transmission, symptoms, and prevention of oxyuriasis in 2012–2013 in Kashan, Central Iran. Materials and Methods: In this cross-sectional study, a total of 500 students in three levels of middle schools were studied. To evaluate the students' knowledge level of oxyuriasis, the standardized questionnaire was distributed and completed. Data were analyzed using statistical software SPSS. Results: Among three levels of students of middle schools, 67.6% of students had average awareness (information), 17.4% had weak information, and 15% had high information. In the assessment of the level of awareness in the first-level students, 23.41% of the students had weak information, 66.4% had average information, and 10.12% had high information. In the second-level students, 12.57% had weak information, 73.14% had average information, and 14.28% had high information. In the third-level middle-school students, 16.76% of students had weak knowledge, 62.87% had average knowledge, and 20.35% had high knowledge. Conclusion: The result of this study shows that knowledge of middle-school students about this infection is good but not sufficient, and it is necessary for teachers and health officers in schools to increase hygienic knowledge of the students and to train about this infection to decrease the damage of personal and social problems.