Purpose-To determine how information professionals in Scotland and in European national libraries perceive linked data as well as if and how they are implementing it. Design/methodology/approach-The authors applied four data collection techniques: a literature review, semi-structured interviews (n=15), online resources analysis (n=26), and an online survey (n=113). They used constant comparative analysis to identify perceived benefits and challenges of linked data implementation, reasons behind adoption or non-adoption of linked data and the issues hindering its implementation in libraries. Findings-Some projects demonstrate linked data's potential to augment the visibility and discoverability of library data, alongside with overcoming linguistic barriers, and supporting interoperability. However, a strong need remains to demonstrate the Semantic Web's potential within libraries. Participants identified lack of expertise and lack of resources/time/staff as implementation barriers. Several other issues remain unsolved, such as licensing constraints, as well as difficulties with obtaining management buy-in for linked data initiatives, even where open data is government-mandated. Practical implications-Information professionals and vendors should collaborate to develop tools for implementation. Advocacy through disseminating and reviewing successful implementations can help to solve practical difficulties and to obtain management buy-in. Originality/value-This is the first known study to present a multinational, comprehensive picture of library linked data implementations and associated librarians' perceptions of linked data.