Gillermo is a distinctive boys' name in United States, ranking #11409 in 2007 with 6 recorded births. This places Gillermo in the bottom 21% of ranked US boys' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 1998 with 21 births ranking #3534. Since 1996, the popularity has decreased by 53.8%. In 2007, approximately 1 in every 345,873 boys born was named Gillermo. FALLING Recent data shows the name is currently falling.