<p>Alphabet knowledge is a vital learning target during early childhood, including for children who are at risk for reading difficulties. For these children, we need to provide effective, efficient, evidence-based instruction. In this study, we examined the uppercase facilitation effect (i.e., children are more likely to identify lowercase letters when they know the corresponding uppercase forms) in the context of alphabet learning and thus its potential to be leveraged as an instructional strategy.&#xa0;Thirty-six 3:5 to 5:5 years old children at risk for reading difficulties due to low alphabet knowledge (18 girls; 50 months old on average; 22 English monolinguals and 14 emergent bilinguals) participated in a within-subjects experiment. Children received 1:1 alphabet instruction on individually selected letters, with other letters serving as controls. We evaluated participating children’s letter name and sound production pre- and post-instruction. We accounted for letters being nested within each child using multilevel logistic regression.&#xa0;Children were more likely to know lowercase letters if they knew the corresponding uppercase letters, regardless of whether the letters were taught or not taught.&#xa0;The uppercase facilitation effect did not apply in the context of alphabet learning. We discuss instructional implications.</p>