Background: Older adults (with and without dementia) are discriminated against at different social levels and often over-generalized in a stereotypical manner is called ageism. Despite advancements in gerontological research, the methodological implementations in the field of ageing and dementia studies have not been shared equally. This article reports on a systematic scoping review of the emerging methodological trends (use and application of research designs and methods) in this combined field.Methods: The study reviewed evidence-based articles published from 2009 to 2018 and indexed in five scientific electronic databases Web of Science, PubMed, Scopus, PsycINFO, and CINAHL complete by following PRISMA-ScR protocol. Both visual scanning of reference lists and hand searching of leading journals were performed in the field of ageing and dementia in order to maximize the search result.Results: A total of 112 papers were included. The review reveals that the predominant form of methodological application was a quantitative design (74.1%) compared to a qualitative (19.6%) and mixed methods (6.2%) in the combined field of ageing and dementia. Furthermore, the data collection instruments mostly used a variety of questionnaire surveys (with and without validated scales) and interviews. Both quantitative, qualitative, and mixed-methods studies have targeted the general public and healthcare professionals by and large, not older adults or people with dementia in particular. Conclusions: The results have important implications for the methodological advancement of ageing and dementia research, as well as for the development of inter-disciplinary and cross-cultural interventions considering the potentialities and limitations of data collection tools. The study provides a first step towards understanding key aspects in any study setting and recommends to be purposeful about what information will be gathered, which measurement tool or instrument is consistent with study purpose, and how the knowledge will be utilized.