The Industrial Control System Security Workshop will be held in Los Angeles, California, Tuesday, December 8, 2015, in conjunction with the Annual Computer Security Applications Conference (ACSAC). ACSAC will be held at the Hilton Los Angeles/Universal City. Supervisory control and data acquisition (SCADA) and industrial control systems monitor and control a wide range of industrial and infrastructure processes such as water treatment, power generation and transmission, oil and gas refining and steal manufacturing. Such systems are usually built using a variety of commodity computer and networking components, and are becoming increasingly interconnected with corporate and other Internet-visible networks. As a result, they face significant threats from internal and external actors. For example, Stuxnet malware was specifically written to attack SCADA systems that alone caused multi-million dollars damages in 2010. The critical requirement for high availability in SCADA and industrial control systems, along with the use of resource constrained computing devices, legacy operating systems and proprietary software applications limits the applicability of traditional information security solutions. The goal of this workshop is to explore new security techniques that are applicable in the control systems context.