A Game Tree is a visual representation used in game theory to illustrate the possible moves in a strategic game. Each node in the tree represents a game state, while the branches indicate the possible actions players can take. This structure helps analyze the outcomes of different strategies and decisions. In a Game Tree, the root node represents the initial state of the game, and each subsequent level shows the progression of moves by players. By exploring the branches, players can evaluate potential strategies and their consequences, aiding in decision-making for games like chess or tic-tac-toe.