The main aim of this study is to find out to what extent do narcissistic personality traits predict internet addiction and cyber bullying in vocational high school students. For this study five hundred and eight vocational high school students (331 male students--66,2%, 169 female students 33,8% and 8 unstated [x-bar] 16,24) from Anatolian side of Istanbul Province have been selected by using cluster sampling method. As data collection tools, Narcissistic Personality Inventory adopted by Atay, Internet Addiction Scale developed by Gunuc and Kayri, and Cyber Bullying Inventory developed by Aricak et.al have been used. The model shows that narcissism has an indirect effect on cyber bullying. As a trait of narcissistic personality "entitlement", significantly predicts "deprivation" and controlling difficulty in internet addiction, besides, the trait of narcissistic personality, "superiority" predicts significantly "social isolation" in internet addiction. It is found out that the scores of narcissistic personality "exploitativeness" negatively predict the scores of internet addiction "controlling difficulty". (Contains 4 tables and 1 figure.)