Brennan is a distinctive boys' name in England & Wales, ranking #2664 in 2025 with 8 recorded births. The name reached its all-time peak in 2002 with 37 births ranking #559. Since 1996, the popularity has decreased by 60.0%. In 2025, approximately 1 in every 33,992 boys born was named Brennan. RISING Recent data shows the name is currently rising.