Gillermo is a distinctive boys' name in United States, ranking #8104 in 2003 with 8 recorded births. The name reached its all-time peak in 1998 with 21 births ranking #3534. Since 1996, the popularity has decreased by 38.5%. In 2003, approximately 1 in every 246,909 boys born was named Gillermo. FALLING Recent data shows the name is currently falling.