Child sexual abuse can be considered a public health problem, since its repercussions throughout life are associated with a greater risk for the development of several psychopathological symptoms. With the increase in internet access in the last 15 years, especially among children and adolescents, the likelihood of opening up to new forms of sexual abuse becomes a concern. Online sexual victimization emerges in this context, bringing relevant evidence of associations with symptoms such as depression, anxiety, suicide and substance use. Therefore, this dissertation aims to investigate early online sexual victimization associated with the manifestation of psychopathological symptoms in adulthood. The dissertation was prepared in the form of articles, being divided into the following steps: an introductory chapter, two articles and a concluding chapter. ARTICLE 1 is a translation and adaptation of an online sexual victimization assessment tool. ARTICLE 2 is an online study to retrospectively investigate, in a sample of young adults and internet users since childhood, the different effects of online and non-online sexual abuse history on symptoms of mental disorders. In Article 1, after all the planned translation and adaptation steps had been successfully completed, confirmatory factor analyzes were performed to verify the reliability and validity indices of the construct. According to factor analysis, the OSV is a second-order factor composed of three first-order factors - insistence (4 items), threats (4 items) and dissemination (2 items). The second order model showed good to excellent model fit between the indices and all items presented significant factor loadings. Therefore, we present the translation, adaptation, as well as reliability and construct validity indices of the scale. In article 2, the results pointed to the effects of early sexual victimization online as risk factors for several psychopathological symptoms. We observed a high prevalence of early online sexual victimization reported by participants, showing that three out of four adults who grew up with internet access experienced online sexual victimization during childhood and/or adolescence. When comparing the control group and the group referring to online sexual victimization before the age of 18, we noticed differences in the manifestations of psychopathological symptoms, indicating that such negative life events may be related to lasting effects on mental health. The data presented in this study suggest that early sexual victimization online is an emerging topic of concern as the internet becomes increasingly accessible to the general population. Our study found extremely relevant results, drawing attention to the importance of building stronger protective resources to prevent children and adolescents from being exposed to such stressful situations.