This document summarizes theories and factors that influence foreign policy decision making. It discusses that foreign policy is shaped by transnational actors, bureaucracies, and decision making processes within governments. Specifically, the executive branch tends to dominate foreign policy decisions due to controlling international relations. However, legislatures, courts, interest groups, and public opinion can also exert influence. Theories explored include rational choice models, bureaucratic politics, and how cognitive biases and group dynamics impact leadership decisions.