People with dementia are under-represented in clinical research, in part due to the ethical and legal complexities of involving people in studies who may lack capacity to consent. Excluding this population from research limits the evidence to inform care. The attitudes and practices of researchers are key to the inclusion of people with dementia in research, however, there are few empirical studies on researchers' perspectives in this area.A cross-sectional study involved researchers in Australia who had experience in the ethical aspects of conducting dementia-related studies with human participants (n = 70). Data were collected via an online survey from November 2017 to January 2018.Most respondents (97%) agreed with the importance of including people at all stages of dementia in research, yet around three-quarters of respondents perceived ethical and legal rules and processes as unduly restrictive or time-consuming. Researchers reported variable practices in assessing prospective participants' capacity to consent to their studies. Various tools are used for this purpose, ranging from tools designed for research (eg, MacArthur Competence Assessment Tool for Clinical Research) to more general cognitive function screens (eg, Mini Mental State Exam).Few respondents (14%) routinely exclude people from studies who are unable to give their own consent, but instead seek permission from proxy decision-makers, such as legally appointed guardians or family carers. Respondents reported positive and negative outcomes of ethics review processes. Positive outcomes included strengthening the protections for participants with cognitive impairment while negative outcomes included delays and inconsistent decisions from different ethics committees.The findings suggest a need for improved strategies in the research context to assess and enhance the decision-making capacity of people with dementia to support appropriate opportunities for inclusion. Education for ethics committees, proxy decision-makers and other gatekeepers is also needed to reduce barriers to participation in research.