The current LGBTQIA+-hostile political climate highlights a growing need among school librarians for evidence-based support addressing inclusive professional practices. To establish a baseline of studies providing this evidence and to identify areas where further research is needed, this study used systematic literature review methodology to examine international empirical research in the field of school and youth librarianship published between the years of 2009 and 2021. The study's objectives were to identify and categorize published empirical research on LGBTQIA+ topics in school and youth librarianship and to identify and categorize gaps in that research, proposing focuses for future research studies. Findings determined that little research has been done to examine LGBTQIA+ inclusive school library services for youth. Also revealed was a monolithic approach to the discussion of LGBTQIA+ identities and expressions. More research in this area and the employment of diverse methodologies to uncover a detailed and expansive picture of what LGBTQIA+ inclusive service means are desperately needed.