Guillaume is a distinctive boys' name in United States, ranking #8428 in 2007 with 9 recorded births. The name reached its all-time peak in 1997 with 19 births ranking #3648. Since 1996, the popularity has decreased by 43.8%. In 2007, approximately 1 in every 230,582 boys born was named Guillaume. FALLING Recent data shows the name is currently falling.