Ambient assisted living (AAL) technologies can provide assistance and support to persons with dementia. They might allow them the possibility of living at home for longer whilst maintaining their comfort and security as well as offering a way towards reducing the huge economic and personal costs forecast as the incidence of dementia increases worldwide over coming decades. However, the development, introduction and use of AAL technologies also trigger serious ethical issues. This paper is a systematic literature review of the on-going scholarly debate about these issues. More specifically, we look at the ethical issues involved in research and development, clinical experimentation, and clinical application of AAL technologies for people with dementia and related stakeholders. In the discussion we focus on: (1) the value of the goals of AAL technologies, (2) the special vulnerability of persons with dementia in their private homes, (3) the complex question of informed consent for the usage of AAL technologies.