This lecture discusses the various actors involved in science and technology for disaster risk reduction, including the public sector, academic institutions, private sector, communities, and volunteers. It explores the roles and responsibilities of these actors at different levels, emphasizing collaboration to enhance disaster preparedness, prevention, and response. The importance of dialogue, cooperation, and leveraging international mechanisms among actors is highlighted, along with the benefits and drawbacks of collaboration. The lecture also covers the UNISDR Science and Technology Conference, emphasizing the mobilization of science to implement the Sendai Framework. References to key documents on disaster risk reduction are provided.