Children with sickle cell disease are at risk of cognitive deficits and somatic growth delays beginning in early childhood. We examined growth velocity from age 2 years (height and body mass index progression over time) and cognitive functioning in 46 children with sickle cell disease 4 to 8 years of age. Height-for-age velocity was not associated with cognitive outcomes. Higher body mass index velocity was associated with higher scores on global cognitive and visual-motor abilities but not processing resources or academic achievement. Body mass index progression over time may be a clinically useful indicator of neurocognitive risk in sickle cell disease, as it may reflect multiple sickle cell disease–related risk factors.