Due to the COVID-19 lockdown, public education has been forced to hold classes online, which increases the time students are on the internet at home. While this situation has significantly reduced the incidence of physical violence between students, cyberbullying has increased sharply, even among younger students. This paper examines a program developed to educate elementary school students on how to best respond to cyberbullying—a social issue that hinders the achievement of sustainable development goals (SDGs). The program was applied to students, and the educational effects were tracked. First, we analyzed education programs in South Korea and the United States that teach students how to cope with cyberbullying, extracted characteristic parts, and developed the online education program in accordance with the current situation in South Korea. Next, we conducted an online education preference survey through an independent sample t-test and one-way ANOVA. As a result, regardless of gender and grade, most study subjects preferred online education. In addition, we conducted a paired sample t-test to determine the prevention and response effects of suggested online education programs. According to the test, the study subjects experienced less cyberbullying and victimization after participating in the online education program. Additional benefits were the students’ increased ability to defend against cyberbullying and a decreased need for defenders and assistants in warding off the cyberbullies.