Suicidal behavior is multidetermined and needs to be investigated in different contexts and environments, including virtual spaces. Research on communication related to mental health on social media is needed. This study was divided into three stages. The first stage aimed to analyze the characteristics and themes of suicide-related posts published on Twitter from places with the lowest and highest suicide death rates in the State of São Paulo -Brazil. In the first stage, a mixed study was conducted with 804 Twitter posts from 2006 to 2018. Associations between post characteristics and prosuicidal postings were submitted for thematic analysis. Cities with lower suicide death rates reported more on the topic, however, most publications in these locations did not expose potentially harmful content and did not express suicidal behavior and suffering. Therefore, suicide posts in one location are not necessarily linked to higher suicide mortality. The second stage of the thesis aimed to investigate the scientific evidence for the recommendations and best practices regarding safe communication about suicidal behavior online. A systematic literature review was carried out and the recommendations were: encouraging the search for help, self-care, describing and monitoring warning signs, understanding suicide as complex and with multiple causes, offering hope, observing online activities, avoiding pejorative connotations, speculating, and describing methods. In the third stage of the thesis, the barriers and facilitators of safe communication about suicide were analyzed. The survey was carried out from October 2018 to February 2019, with 338 individuals. The data was collected by Google Forms and submitted for Thematic Analysis. The identified facilitators were: incentive to seek professional help, the propensity to offer help, and the belief in the possibility of overcoming. The barriers were related to stigma, accountability, refusal of help, difficulty in offering help, and concern with unpreparedness when dealing with the topic. Among the ambivalent possibilities, issues related to religiousness and also to counseling / previous experience arose. The findings of this study can contribute to the improvement of safe communication about suicidal behavior, especially in virtual environments.