The article addresses the awareness of manifestations and risks of sexual abuse on cyberspace of secondary school students in Hanoi. The survey results are based on collecting opinions from 411 students in 2 Secondary schools in Hanoi. The results of the study show that students have some initial understanding of behavioral manifestations, risks and how to respond to the risk of sexual abuse in cyberspace. However, most students are still confused in identifying online sexual abuse. They only guess based on their emotions and do not have a proper understanding of the risks from this issue. Therefore, improving knowledge and skills to respond to the risk of sexual abuse in cyberspace for secondary school students is an urgent need in schools today.