This chapter provides a synopsis of the research into decision making, highlighting the different types of decisions that sports officials are confronted with. Focusing primarily on more subjective decisions, I discuss the importance of having an officiating philosophy, accounting for safety, fairness, accuracy, and entertainment. Decision accuracy and decision appropriateness are discussed from a naturalistic standpoint and I argue the significance of context for making effective decisions. The terms declarative knowledge (knowing what) and procedural knowledge (knowing how) are introduced, to highlight the basis upon which sports officials’ decisions are made, and think-aloud protocols are discussed as processes for revealing decision processes. I draw attention to the importance of situation awareness in (i) attending to the right cues, (ii) understanding what they mean, which creates the capacity to (iii) predict likely future events, allowing officials to effectively read the game and make appropriate decisions. An approach to decision training using experts in their real-world context, with point-of-view video recording and eye-tracking-glasses is used to reveal the knowledge that informs expert decision processes in the context of touch (rugby/football). This results in a decision tree as an aid to develop expertise in less-experienced officials.