In the field of international relations, a sphere of influence (SOI) is a spatial region or concept division over which a state or organization has a level of cultural, economic, military, or political exclusivity.
While there may be a formal alliance or other treaty obligations between the influenced and influencer, such formal arrangements are not necessary and the influence can often be more of an example of soft power. Similarly, a formal alliance does not necessarily mean that one country lies within another's sphere of influence. High levels of exclusivity have historically been associated with higher levels of conflict.