Public libraries, archives, and museums have identifiable differences related to their founding missions and play many roles in today’s cultural sector and broader society, yet LAM institutions’ professional activities appear very similar. Moreover, increased digitization of LAM collections allows for increased collaboration and convergence across the institutions, and the merging of L, A, and M education at the tertiary level nurtures a common professional knowledge base. How are the LAM professions developing in relation to each other; are they growing together or apart? This paper analyzes questionnaire responses reflecting European LAM professionals’ perceptions of their roles as cultural professionals and how this influences their likelihood to collaborate with others in the LAM sector. Collaboration is prevalent between the three types of professionals studied. Forty-six percent of librarians confirm that they collaborate with archives and/or museums, 60% of archives report collaborating with libraries and museums, and 73% of museologists collaborate with libraries and/or archives. LAM professionals perceive their roles as distinct and closely tied to the core of their social mission. There are various factors influencing collaboration among Library, Archive, and Museum (LAM) professionals.