Getting an accurate dementia diagnosis can be a long and challenging road for patients and their families. This systematic review identified 20 studies focused on missed and delayed diagnosis of dementia and dementia subtypes. People with rare subtypes, such as young-onset dementia, experienced significant delays in obtaining an accurate diagnosis, as did minoritized patients. Misdiagnosis was associated with increased costs until the time of correct diagnosis. None of the studies assessed the emotional impact misdiagnosis has on patients and caregivers, which the authors recognize as an urgent area for future research.