**Abstract**

Geological Carbon Sequestration (GCS) is an effective way to fight against global warming by capturing and injecting CO2 into geological formations to ensure permanent storage as well as to prevent the environmental and health threats posed by carbon dioxide emissions. Security has been a key factor in the social acceptance of this technology, besides the issues related to economics. From a scientific point of view, the safety issues during CO2 injection and long-term storage are highly related to geomechanics. This chapter provides a basic knowledge of the geomechanical issues involved in the GCS process to increase the understanding of safety issues and to improve the social acceptance of the technology among researchers and those interested in the technology.

**Keywords:** geological carbon sequestration, trapping mechanisms, stress change, caprock integrity, well integrity, induced seismicity
