Alastair is a distinctive boys' name in United States, ranking #2675 in 2018 with 46 recorded births. The name reached its all-time peak in 2025 with 67 births ranking #2147. Since 1996, the popularity has increased by 170.6%. In 2018, approximately 1 in every 39,467 boys born was named Alastair. RISING Recent data shows the name is currently rising.