Accumulating evidence demonstrates that blood pressure variability (BPV) may contribute to target organ damage, causing coronary heart disease, stroke, and renal disease independent of the level of blood pressure (BP). Several lines of evidence have also linked increased BPV to a higher risk of cognitive decline and incident dementia. The estimated number of dementia cases worldwide is nearly 50 million, and this number continues to grow with increasing life expectancy. Because there is no effective treatment to modify the course of dementia, targeting modifiable vascular factors continues as a top priority for dementia prevention. A clear understanding of the role of BPV in dementia may shed light on the etiology, early prevention, and novel therapeutic targets of dementia, and has therefore gained substantial attention from researchers and clinicians. This review summarizes state-of-art evidence on the relationship between BPV and dementia, with a specific focus on the epidemiological evidence, the underlying mechanisms, and potential intervention strategies. We also discuss challenges and opportunities for future research to facilitate optimal BP management and the clinical translation of BPV for the risk assessment and prevention of dementia.