The main actors in international relations include nation-states, international organizations, non-governmental organizations (NGOs), multinational corporations, and transnational advocacy networks. Nation-states are the primary entities, engaging in diplomacy, treaties, and conflict resolution. International organizations like the UN facilitate cooperation and address global challenges. NGOs often advocate for humanitarian issues and human rights, influencing policy and exposing injustices. Multinational corporations wield significant economic power and can affect national policies through investment and trade. Each actor plays a unique role in shaping international dynamics, contributing to the complexity of global governance and policy-making.