Prior research suggests a link between curiosity and metacognition, but how curiosity is involved in two key metacognitive processes -- metacognitive monitoring (i.e., assessing one's cognitive states and performance) and metacognitive control (i.e., adjusting decisions and behaviors) -- remains unclear. In three experiments (N = 264) participants first saw a general knowledge question and answer options on each trial. In Experiment 1, participants selected an answer and rated their curiosity and confidence. In Experiment 2, participants rated their curiosity and, instead of rating confidence, could either select an answer or opt out; at the end, they answered the previously skipped questions. Participants showed lower confidence (Experiment 1) and were more likely to opt out (Experiment 2) on trials where they provided incorrect rather than correct answers. In both experiments they reported greater curiosity on incorrect-answer trials. These findings suggest that curiosity signals metacognitive monitoring and drives control. Experiment 3A and 3B further examined the impact of curiosity on metacognitive control and showed that exposure to others' curiosity influenced participants' metacognitive control. Together, these results provide initial direct evidence that curiosity actively guides metacognitive processes. They also highlight that curiosity helps align individuals' metacognitive experiences with those of others thereby further impacting their own metacognitive processes.