The article aims to verify whether volunteers working in the same branch of the nonprofit sector (e.g., culture, emergency services, and charity) share any similarities with respect to their motivation profiles. Moreover, the study tries to identify the mechanisms responsible for such inter–branch “motivation sorting.” In particular, three mechanisms are considered: functional matching, motivations to affordances matching, and motivation alignment. The data used in the analysis come from an original survey conducted among volunteers in Poland with the use of the Volunteer Functions Inventory (Clary, Snyder & Stukas, 1996). This questionnaire allows the identifying of six types of volunteer motivations: career, social, protective, understanding, enhancement, and values. The motivation profile of volunteers working in seven branches of the nonprofit sector is compared. The results indicate that the most distinctive group with respect to the motivation profile was made up of volunteers working in tourism and sports as well as emergency service volunteers. It was in the latter group that some traces of the motivation alignment and/or motivation to affordances matching were identified. The identification of some homogeneity of motivations within particular branches of the nonprofit sector is a valuable finding from the point of view of volunteer recruitment and retention.