First responders and professionals in hazardous occupations undergo intense training and evaluation to enable them to efficiently and effectively mitigate risk and damage. For example, helicopter pilots train with multiple simulations that increase in complexity before they fly real aircraft. However, in the industrial control systems domain, where incident response professionals help detect, respond and recover from cyber incidents, there is no official categorization of training environments, let alone training regimens. To address this gap, this chapter provides a categorization of industrial control training environments based on realism. Four levels of environments are proposed and mapped to Bloom’s Taxonomy. The categorization enables organizations to determine the cyber training environments that best align with their training needs and budgets.