Guillermo is a distinctive boys' name in United States, ranking #832 in 2024 with 297 recorded births. The name reached its all-time peak in 1998 with 693 births ranking #369. Since 1996, the popularity has decreased by 57.1%. In 2024, approximately 1 in every 5,775 boys born was named Guillermo. STABLE Recent data shows the name is currently stable.