A kind of hemoglobinopathy known as sickle cell anemia (SCA) is characterized by aberrant hemoglobin molecules. The most frequent neurological side effects linked to SCA include neurocognitive dysfunction, asymptomatic cerebral infarction, and ischemic stroke. This study aims to investigate the relationship between SCA and cognitive dysfunction. We systematically searched electronic databases like PubMed, MEDLINE, Science Direct, and Scopus. Two independent reviewers screened and extracted data from eligible studies. Eighteen studies, including 2,457 participants in total and nearly half of them 1,151 (46.8%) were males, were included in our data. The prevalence of cognitive dysfunction in the adult population ranged from 11.5% to 70%. Cognitive dysfunction among adults was significantly associated with poorer educational status, reduced family income, decreased kidney function, older age, stroke history, and vasculopathy. The prevalence of cognitive dysfunction in children ranged from 10.2% to 68.2%. The decline in cognitive function among adults was significantly associated with children over the age of four, abnormal transcranial Doppler and previous stroke, school absence, age beyond 13, and increased BMI. Cognitive function deficiencies are a defining feature of SCA that affects people of all ages. These findings suggest that if cognitive decline is not slowed down, or better still, stopped, medical interventions targeting a variety of sequelae in this population will be ineffective. Future analyses of this population's cognition should evaluate the environmental and other biological variables.