Willem is a distinctive boys' name in United States, ranking #1516 in 1999 with 75 recorded births. The name reached its all-time peak in 2003 with 122 births ranking #1208. Since 1996, the popularity has increased by 63.0%. In 1999, approximately 1 in every 25,601 boys born was named Willem. STABLE Recent data shows the name is currently stable.