This study aimed to investigate the use of volunteers in special libraries in the Republic of Ireland. The research showed the various effects of volunteers on library services. Seven qualitative semi-structured interviews with librarians and staff at various libraries were conducted. Volunteers’ duties varied depending on the services offered by each special library. Interviewees identified a range of positive and negative effects. Volunteers helped libraries to offer improved and additional services and broadened the shared skills within the library team. A higher volume of work was completed. Volunteer networks became available for libraries to consult in future. The training and time required to prepare each volunteer was identified as a challenge. Volunteer policies were not present in every library, which may result in greater challenges for the staff and volunteers. The experiences and opinions of library staff were positive and showed a readiness to recruit volunteers again in the future.