In international relations, credibility is the perceived likelihood that a leader or a state follows through on threats and promises that have been made. Credibility is a key component of coercion (i.e. compellence and deterrence), as well as the functioning of military alliances. Credibility is related to concepts such as reputation (how past behavior shapes perceptions of an actor's tendencies) and resolve (the willingness to stand firm while incurring costs). Reputation for resolve may be a key component of credibility, but credibility is also highly context-dependent.

Credibility may be determined through assessments of power, past reputation, current interests, and signaling. Situational and dispositional factors may affect perceptions of credibility. Misperception and miscommunication can lead to erroneous assessments of credibility. Assessments of reputation may be linked to specific leaders, as well as states. Leaders and diplomats generally consider the credibility of their state to be of paramount importance.

Much of the scholarship on coercion focuses on the credibility of coercive threats as a key component of the success of coercive diplomacy. According to Thomas Schelling, a reputation for resolve "is one of the few things worth fighting over."

Successful coercion frequently revolves around a demonstration of capabilities and resolve, both of which enhance the credibility of attempts to coerce others. According to Richard Ned Lebow, a credible threat entails:

Robert Art identifies 8 prerequisites for a successful compellence strategy:

Matthew Fuhrmann and Todd Sechser argue that there are three main components to credibility in coercion:

According to Anne Sartori, states rarely seek to obtain goals through bluffing, because doing so undermines their reputation in future crises. Survey experiment data from Barbara Walter and Dustin Tingley confirm the findings of Sartori's study, as they find that people "invest more heavily in reputation building if they believe a game will be repeated many times."

Credibility (or reputation) refers to the degree to which an actor is expected to uphold their commitments based on past behavior. In terms of credible coercive diplomacy, credibility entails that defiance will be met with punishment, and that compliance will be met with restraint. One of the main problems in coercive diplomacy is that it is hard to credibly signal that compliance will not lead to punishment. Some scholars have argued that when great powers increase their power, their credibility to engage in restraint decreases, which may lead weaker adversaries to be less likely to comply with great power threats.