Hindsight bias is the tendency for individuals to claim that past events were more predictable than they actually were, while metacognition is awareness of one’s own thoughts. In this experiment, we will investigate metacognitive hindsight bias, which refers to the extent in which people recall how confident they were in their success in a cognitive task (e.g., answering a knowledge question). Past research has shown that hindsight bias is a robust phenomenon found throughout the life span, while metacognition improves as children mature from kindergarten to grade 12 (Schneider, 2010). However, no research has investigated metacognitive hindsight bias across the developmental trajectory. Therefore, the goal of this study is to expose developmental patterns in metacognitive hindsight bias as people get older.