Guillermo is a distinctive boys' name in United States, ranking #834 in 2023 with 292 recorded births. The name reached its all-time peak in 1998 with 693 births ranking #369. Since 1996, the popularity has decreased by 57.8%. In 2023, approximately 1 in every 5,851 boys born was named Guillermo. STABLE Recent data shows the name is currently stable.