Early sexual activity has been associated with unplanned pregnancy and sexually transmitted infections. In recent decades, the prevalence of early sexual activity and social media use has increased. However, the relationship between these variables has been little studied. Consequently, we examined the relationships of some factors present in the family and personal environment with early sexual activity in adolescents who use and do not use the WhatsApp and Facebook platforms. Through a cross-sectional study, data from 1328 adolescents aged 13 to 19 years were analyzed. Data collection was carried out using a self-administered questionnaire. Of the total participants, 35.7% reported early sexual activity, and 37.7% reported using social networks such as WhatsApp and Facebook. The mean age of onset of sexual activity was 15.59 ± 1.56 years. Multivariate logistic regression analysis showed significant associations of not studying (adjusted OR 4.70; CI 95% 1.31-16.78), consuming alcohol (adjusted OR 3.71; CI 95% 2.44-5.65) and having parents who consumed alcoholic beverages in the home (adjusted OR 1.48; 95% CI 1.03-2.12) with ESA. In the family and personal environment, some factors favored early sexual activity in young people who used the WhatsApp and Facebook applications. This information should be used by authorities in the health and education sectors to strengthen preventive programs targeting health risk habits and behaviors in adolescents.