In the United States, prospective adoptive parents often express preferences related to race. In two studies, we examined whether implicit racial bias against Black people may contribute to disparities in much less willingness to adopt Black children. The first study ( = 510) assessed individuals' implicit racial bias and their willingness to adopt a Black child. The second study ( = 2,001,652) used U.S. state-level implicit racial bias to predict adoption rates of Black foster children in each U.S. state. Greater implicit racial bias predicted less willingness to adopt Black children and less frequent adoptions of Black foster children. Implicit bias contributed to these disparities above and beyond explicit bias, with implicit bias having a 43% larger effect size than explicit bias on willingness to adopt a Black child. These are the first findings to demonstrate the role implicit bias plays in explaining large disparities between Americans' willingness to adopt Black and White children.