Inclusion Criteria:  Participants who meet all the following criteria will be eligible for enrollment:  Willing and able to provide written informed consent (ages ≥ 18 years) or parental/guardian consent and participant assent (age <18 years) per local regulations Male or female participants with documented diagnosis of sickle cell disease (all genotypes) Undergoing treatment with Oxbryta according to the Oxbryta USPI  Exclusion Criteria:  Participants meeting any of the following criteria will not be eligible for study enrollment:  Current participation or prior participation within ≤1 year before enrollment in an investigation clinical trial or expanded access program, in which the participant received voxelotor treatment Medical, psychological, or behavioral condition that, in the opinion of the study doctor, would confound or interfere with evaluation of safety and/or effectiveness of the study drug, prevent compliance with the study protocol; preclude informed consent; or render the participant unable/unlikely to comply with the study procedures