A State Machine is a computational model used to design systems that can be in one of a finite number of states at any given time. It transitions between these states based on specific inputs or conditions, allowing it to respond to different scenarios. This concept is widely used in computer science, engineering, and various applications like video games and user interfaces. In a state machine, each state represents a particular condition or situation, while transitions define how the system moves from one state to another. For example, a simple traffic light can be modeled as a state machine with states like Red, Yellow, and Green, transitioning based on a timer or sensor input.