Hate speech incites violence and has devastating effects on communities. Its scale and impact are nowadays amplified by new technologies and social media to the point that online hate speech has become one of the most frequent methods for spreading divisive rhetoric and violent ideologies. Alice Nderitu, the Special Adviser of the UN Secretary-General on the Prevention of Genocide tells about the real world examples of crimes committed as a result of hate speech, and how engaging local communities holds the key to preventing future incidents. The United Nations has a long history of mobilizing the world against hatred of all kinds to defend human rights and advance the rule of law. The impact of hate speech cuts across numerous existing United Nations areas of focus, from human rights protection and prevention of atrocity crimes to sustaining peace and achieving gender equality and supporting children and youth.