For reasons of human health and sustainability, there is a growing interest in the potential of integrated nature-based interventions in healthcare. However, it is not clear which quality criteria underlie these interventions. Here, we develop a study protocol for a scoping review to explore potential quality criteria relating to the design, implementation and evaluation of nature-based interventions in healthcare institutions. The literature search will be conducted in PubMed, MEDLINE, Web of Science and Scopus, focusing on studies published in English between January 2005 and April 2023. The Joanna Briggs Institute Scoping Review methodology and Preferred Reporting Items for Systematic Reviews with extension for scoping reviews will be used. Search terms were developed stepwise and in consultation with the interdisciplinary research team and the project steering group. Two researchers will perform the screening of the papers independently. Using descriptive content analysis, identified quality criteria will be classified according to the applied theoretical frameworks, outcomes, levels (institutional, professional and patient) and the domains of biodiversity, human health or intervention processes. Ultimately, this descriptive work will result in a set of quality indicators and a prototype nature-based intervention quality assessment framework, which will be presented to the project steering group and multi-stakeholder assembly for further refinement.