Affect labeling is an implicit emotional regulation strategy that can be simply described as "putting feelings into words". Specifically, it refers to the idea that explicitly labeling one's, typically negative, emotional state results in a reduction of the conscious experience, physiological response, and/or behavior resulting from that emotional state. For example, writing about a negative experience in one's journal may improve one's mood. Some other examples of affect labeling include discussing one's feelings with a therapist, complaining to friends about a negative experience, posting one's feelings on social media or acknowledging the scary aspects of a situation.

Affect labeling is an extension of the simple concept that talking about one's feelings can make oneself feel better. Although this idea has been used in talk therapy for over a century, formal research into affect labeling has only begun in recent years. Already, researchers have quantified some of the emotion-regulatory effects of affect labeling, such as decreases in subjective emotional affect, reduced activity in the amygdala, and a lower skin conductance response to frightening stimuli. As a consequence of being a relatively new technique in the area of emotion regulation, affect labeling tends to be compared to, and is often confused with, emotional reappraisal, another emotion-regulatory technique. A key difference between the two is that while reappraisal intuitively feels like a strategy to control one's emotions, affect labeling often does not. Even when someone does not intend to regulate their emotions, the act of labeling one's emotions still has positive effects.

Affect labeling is still in the early stages of research and thus, there is much about it that remains unknown. While there are several theories for the mechanism by which affect labeling acts, more research is needed to provide empirical support for these hypotheses. Additionally, some work has been done on the applications of affect labeling to real-world issues, such as research that suggests affect labeling may be commonplace on social media sites. Affect labeling also sees some use in clinical settings as a tentative treatment for fear and anxiety disorders. Nonetheless, research on affect labeling has largely focused on laboratory studies, and further research is needed to understand its effects in the real world.

The notion that talking about or writing down one's feelings can be beneficial is not a recent one. People have kept diaries for centuries, and the use of talk therapy dates back to the beginnings of psychotherapy. Over the past few decades, the idea that putting one's feelings into words can be beneficial has been shown experimentally. More recently, the concept of affect labeling has grown out of this literature, honing in on the emotion regulation aspect of the benefits of vocalizing feelings.

In recent years, research on affect labeling has mostly focused on proving its applicability as an emotion regulation strategy. Although some research exists on the behavioral and neural mechanisms behind its effectiveness, this area of study is still in its early, speculative stages.

When engaging in affect labeling, subjects subjectively report lower levels of emotional affect than they do in identical conditions without the affect labeling. This effect is not only found when subjects rate their own emotional state, but also when they label the emotion displayed or evoked by stimuli such as images.

Autonomic responses characteristic of various emotions may decrease after performing affect labeling. For instance, upon quantifying their level of anger on a rating scale, subjects subsequently experienced decreases in heart rate and cardiac output. Research also indicates that giving labels to aversive stimuli results in a lower skin conductance response when similar aversive stimuli are presented in the future, implying affect labeling can have long-term effects on autonomic responses.

Research has found that engaging in affect labeling results in higher brain activity within the ventrolateral prefrontal cortex (vlPFC), and reduced activity in the amygdala when compared to other tasks involving emotional stimuli. In addition, evidence from brain lesion studies also point to the vlPFC's involvement in the affect labeling process. Subjects with lesions to the right vlPFC were less able to identify the emotional state of a character throughout a film. This implies that the region is required in order for affect-labeling to take place. Additionally, it has been shown through meta-analysis that while the amygdala is found to be active in tasks involving emotional stimuli, activity is lower when subjects had to identify the emotions rather than simply passively viewing the stimuli.