This article develops an affect theory of social exchange, which explains how and when emotions generated by social exchanges influence the strength of ties to relations, groups, or networks. The theory posits that social exchange produces positive or negative global feelings, which are either rewarding or punishing. These feelings are attributed to social units (relations, groups, networks) based on the degree of jointness in the exchange task. The jointness of the task is highest when actors find it difficult to distinguish their individual contributions (nonseparability) and perceive shared responsibility for success or failure. The theory elaborates on how different exchange structures affect these conditions and, consequently, cohesion and solidarity. It also discusses the implications for network-to-group transformations. The theory emphasizes the role of emotions in social exchange, moving beyond traditional Skinnerian and rational choice perspectives. It argues that emotions are critical to understanding how social exchanges promote or inhibit solidarity in relations or groups. The theory is supported by empirical research and provides a framework for understanding the emotional processes in various social contexts.This article develops an affect theory of social exchange, which explains how and when emotions generated by social exchanges influence the strength of ties to relations, groups, or networks. The theory posits that social exchange produces positive or negative global feelings, which are either rewarding or punishing. These feelings are attributed to social units (relations, groups, networks) based on the degree of jointness in the exchange task. The jointness of the task is highest when actors find it difficult to distinguish their individual contributions (nonseparability) and perceive shared responsibility for success or failure. The theory elaborates on how different exchange structures affect these conditions and, consequently, cohesion and solidarity. It also discusses the implications for network-to-group transformations. The theory emphasizes the role of emotions in social exchange, moving beyond traditional Skinnerian and rational choice perspectives. It argues that emotions are critical to understanding how social exchanges promote or inhibit solidarity in relations or groups. The theory is supported by empirical research and provides a framework for understanding the emotional processes in various social contexts.