Meningeal lymphatics play a critical role in the clearance of waste products from the central nervous system (CNS) and are involved in maintaining brain homeostasis. This study shows that meningeal lymphatics drain macromolecules from the CNS (cerebrospinal fluid and interstitial fluid) into the cervical lymph nodes. Impairment of meningeal lymphatic function slows the paravascular influx of CSF macromolecules and efflux of ISF macromolecules, leading to cognitive impairment. Treatment with vascular endothelial growth factor C (VEGF-C) enhances meningeal lymphatic drainage, improving brain perfusion and learning and memory performance. In Alzheimer's disease (AD) models, disruption of meningeal lymphatic vessels promotes amyloid deposition in the meninges, which closely resembles human meningeal pathology and aggravates parenchymal amyloid accumulation. These findings suggest that meningeal lymphatic dysfunction may be an aggravating factor in AD pathology and age-associated cognitive decline. Augmentation of meningeal lymphatic function could be a promising therapeutic target for preventing or delaying age-associated neurological diseases. Aging is a major risk factor for many neurological pathologies, including AD. The CNS lacks lymphatic vasculature, and waste removal is mainly through a paravascular route. The (re)discovery of meningeal lymphatic vessels has prompted reassessment of CNS waste clearance pathways. Aging is associated with peripheral lymphatic dysfunction, and age-related decline in meningeal lymphatic function may contribute to the accumulation of amyloid beta (Aβ) in the brain. This study shows that meningeal lymphatic dysfunction impairs CSF/ISF drainage and affects brain perfusion, leading to cognitive deficits. Meningeal lymphatic ablation in mice results in reduced CSF drainage, impaired brain perfusion, and cognitive deficits. Treatment with VEGF-C improves meningeal lymphatic function and cognitive performance in aged mice. In AD models, meningeal lymphatic dysfunction exacerbates amyloid pathology. These findings highlight the importance of meningeal lymphatic function in maintaining brain health and suggest that targeting meningeal lymphatics could be a promising therapeutic strategy for AD and age-related cognitive decline.Meningeal lymphatics play a critical role in the clearance of waste products from the central nervous system (CNS) and are involved in maintaining brain homeostasis. This study shows that meningeal lymphatics drain macromolecules from the CNS (cerebrospinal fluid and interstitial fluid) into the cervical lymph nodes. Impairment of meningeal lymphatic function slows the paravascular influx of CSF macromolecules and efflux of ISF macromolecules, leading to cognitive impairment. Treatment with vascular endothelial growth factor C (VEGF-C) enhances meningeal lymphatic drainage, improving brain perfusion and learning and memory performance. In Alzheimer's disease (AD) models, disruption of meningeal lymphatic vessels promotes amyloid deposition in the meninges, which closely resembles human meningeal pathology and aggravates parenchymal amyloid accumulation. These findings suggest that meningeal lymphatic dysfunction may be an aggravating factor in AD pathology and age-associated cognitive decline. Augmentation of meningeal lymphatic function could be a promising therapeutic target for preventing or delaying age-associated neurological diseases. Aging is a major risk factor for many neurological pathologies, including AD. The CNS lacks lymphatic vasculature, and waste removal is mainly through a paravascular route. The (re)discovery of meningeal lymphatic vessels has prompted reassessment of CNS waste clearance pathways. Aging is associated with peripheral lymphatic dysfunction, and age-related decline in meningeal lymphatic function may contribute to the accumulation of amyloid beta (Aβ) in the brain. This study shows that meningeal lymphatic dysfunction impairs CSF/ISF drainage and affects brain perfusion, leading to cognitive deficits. Meningeal lymphatic ablation in mice results in reduced CSF drainage, impaired brain perfusion, and cognitive deficits. Treatment with VEGF-C improves meningeal lymphatic function and cognitive performance in aged mice. In AD models, meningeal lymphatic dysfunction exacerbates amyloid pathology. These findings highlight the importance of meningeal lymphatic function in maintaining brain health and suggest that targeting meningeal lymphatics could be a promising therapeutic strategy for AD and age-related cognitive decline.