Background: Despite the benefits offered by biosimilars in terms of cost savings and improved patient access to biological therapies, and an established regulatory pathway in Europe, biosimilar adoption is challenged by a lack of knowledge and understanding among stakeholders such as healthcare professionals and patients about biosimilars, impacting their trust and willingness to use them. In addition, stakeholders are faced with questions about clinical implementation aspects such as switching. Objective: This study aims to provide recommendations on how to improve biosimilar understanding and adoption among stakeholders based on insights of healthcare professionals (physicians, hospital pharmacists, nurses), patient(s) (representatives) and regulators across Europe. Method: The study consists of a structured literature review gathering original research data on stakeholder knowledge about biosimilars, followed by semi-structured interviews across five stakeholder groups including physicians, hospital pharmacists, nurses, patient(s) (representatives) and regulators across Europe. Results: Although improvement in knowledge was observed over time, generally low to moderate levels of awareness, knowledge and trust towards biosimilars among healthcare professionals and patients are identified in literature (N studies = 106). Based on the provided insights from interviews with European experts (N = 44), a number of challenges regarding biosimilar stakeholder understanding are identified, including a lack of practical information about biosimilars and their use, a lack of understanding about biosimilar concepts and a lack of knowledge about biologicals in general. Misinformation by originator industry is also believed to have impacted stakeholder trust. In terms of possible solutions and actions to improve stakeholder understanding, broad support exists to (1) organize initiatives focussed on explaining the rationale behind biosimilar concepts and the approval pathway, (2) invest in education about biologicals in general, (3) develop clear and one-voice regulatory guidance about biosimilar interchangeability and switching across Europe, (4) disseminate real-world clinical biosimilar (switch) data, (5) share biosimilar experiences by key opinion leaders and among peers, (6) provide practical biosimilar product information, (7) provide guidance about biosimilar use, (8) actively counterbalance misinformation and organize information initiatives by neutral entities, (9) organize multi-stakeholder informational and educational efforts, aligning information between involved stakeholder groups and (10) design initiatives in a way that ensures active information uptake. Furthermore, interviewees argue that governments should be proactive in these regards. Conclusions: This study argues in favour of a structural, multi-stakeholder framework at both European and national level to improve stakeholder biosimilar understanding and acceptance. It proposes a number of actionable recommendations that can inform policy making and guide stakeholders, which can contribute to realizing healthcare system benefits offered by biosimilar competition. [ABSTRACT FROM AUTHOR]