Research with people with dementia can be ethically challenging because of the effects of dementia on cognitive function. A narrative literature review of ethical human dementia research was conducted, highlighting ethical challenges that can be categorised under the following themes: substitute judgment; how capacity can vary due to risks; barriers to recruiting people with dementia; how to determine capacity to give consent; and gaining assent rather than consent from participants. The results of the review were further analysed in relation to the Australian National Statement on Ethical Conduct in Human Research (National Statement). Gaps in the National Statement include: how capacity should be determined; what defines best interests; how assent and dissent by someone with dementia should be determined and respected; and whether or not people with dementia should be included in high-risk research.