COVID-19 an epidemic that can infect all ages, including children. The purpose of this study was to determine the factors related to the behavior of preventing the transmission of COVID-19 at the Darul Arqom Muhammadiyah Islamic Boarding School in 2021. This type of research was quantitative with a Cross Sectional approach. The data collection technique used a questionnaire which was distributed directly to the students at the Islamic Boarding School. The instrumen used is a questionnaire. The population in this study were all santri and female students in the modern Islamic boarding school of Muhammadiyah Darul Arqom. The sample in this research is 127 respondents. The sampling technique used is Non Probability Sampling with the Quota Sampling method. Analysis of the data used is univariate and bivariate using Chi Square Test. Results: Based on the results of the univariate analysis, it showed that the most students had poor COVID-19 transmission prevention behavior as much as 71.1%. Most of the students in the Darul Arqom Islamic Boarding School are early teens (12-16 years old) 89.8%. Most of the students are female 55.1%. MTS 73.2%, most students have good knowledge regarding COVID-19 prevention. Most of the students' attitudes were in the negative category, as many as 63.8%. At most the availability of facilities and infrastructure is not good at 75.6%. Most students are exposed to good information media, 52%. Santri get support from teachers 52%, religious leaders 78%, peers 52.8% health workers do not support 55.1%. The religious factor of the santri decreased after the pandemic by 62.2%. There is a significant relationship between knowledge (Pvalue = 0, 022), attitudes (Pvalue = 0.042) peer support (Pvalue = 0, 028), teacher support (Pvalue = 0, 037), support from community leaders outside the Islamic boarding school (Pvalue = 0, 163), the role of health workers (Pvalue = 0, 021), exposure to information media (Pvalue = 0,036), and there was no relationship between Age (Pvalue= 0,838), gender (Pvalue = 0,545), education level (Pvalue = 0,545), Class (Pvalue= 0,182), availability of facilities and infrastructure (Pvalue = 0,578), religious factors (Pvalue = 0,163).