Learning the relationships between letters and sounds is a key component of early literacy development and a central aim during the first year of school. Introducing one new letter a week is the most common approach in many countries, but little is known about how the pace of letter instruction contributes to the development of early literacy skills. This study used a natural experiment to investigate how a faster pace of letter instruction influences the development of letter knowledge, word reading, and spelling during the first year of school. Regression analysis showed that a faster pace yielded significantly better results for all outcome measures, and logistic-regression models showed that the lowest-performing children benefited more than the highest-performing one from a faster pace. The study concludes with a discussion of those novel findings and suggestions about their implications for teaching practice.