The number of social media users continues to increase. In line with this, cyberbullying is something that needs to be considered by looking at the trigger factors. Psychological loneliness and emotional regulation are closely related to the cyberbullying perpetration. The aim of this research is to examine the role of psychological loneliness toward the emotional regulation cyberbullying perpetration among late adolescence in social media YouTube. This research involved 150 respondents, age 18 to 21 years old. The instruments were UCLA Loneliness Scale (version 3), Emotion Regulation Questionnaire, and Cyberbullying Offending Scale for screening. Retrieval of data using purposive sampling and the type of research used is non-experimental correlation research with quantitative methods. Hypothesis testing uses SPSS with regression analysis techniques between psychological loneliness and emotion regulation. The result is t (150) = -3.107, p < 0.05, showed there is a significant role of the psychological loneliness toward the emotional regulation.