In this chapter, we briefly introduce the security and privacy issues in ISAC, which is of great importance in practice. There have been many studies. However, most of them focus on the attacks on sensing, either proactively jamming the sensing procedure or passively eavesdropping the information of the sensed target. It is essentially not different from security issues in radar-sensing networks, while the interaction with communications is not taken into account. Therefore, it is still an open problem to disclose the new security and privacy issues stemming from the interactions between communications and sensing in ISAC. Hence, we do not enumerate many existing studies on ISAC security in this chapter.