This thesis investigates various aspects of quantum information and quantum gravity, with results that can be categorized into two main sections. The first two chapters employ powerful techniques in quantum field theory and quantum information theory to gain insights into quantum gravity through the AdS/CFT correspondence. Chapter Two focuses on using constraints on entropy from quantum information theory to explore and constrain “quantum entanglement islands” in cosmological settings, while Chapter Three employs the bound on quantum chaos and conformal bootstrap techniques to gain a better understanding of focusing in quantum gravity. The subsequent chapters shift the focus to understanding quantum gravity directly, particularly in simple low dimensional gravity and topological string theory scenarios. Chapter Four and Five center on calculating the entanglement entropy in topological string theory and its Chern-Simons dual. Finally, in Chapter Six, the study uncovers gravitational models that are dual to an ensemble average of deformed WZW models.