Loneliness has been becoming an issue that needs to be taken notice of, specifically in Indonesia. It is often overlooked by people thinking that the state of being lonely is momentary and will not cause any harm whereas it could affect one’s psychological and physical well-being. One factor that contributed partly was attachment style which became the ultimate reason of doing a study to see whether it affects loneliness. 147 Indonesian females and males, age 13 to 17 were involved in the study using snowball sampling. This study aimed to understand the connection between each variable by also proposing 4 hypotheses: secure attachment style negatively correlates and affects loneliness while fearful, dismissing, and preoccupied will have positive correlations with effects on loneliness. The result came as: Secure (F(1,147) = 42.027, p = .00, R2 = 22.5%), Fearful (F(1,147) = 5.173, p = .024, R2 = 34%), Preoccupied (F(1,147) = 6.139, p = .014, R2 = 4.1%), and Dismissing (F(1,147) = 6.139, p = .014, R2 = 4.1%), meaning that all types of attachment styles do affect loneliness.