Boy Names That Start With O

Ranked in the United Kingdom in 2025, with birth trends and peak years.

O is the 10th most common first initial for baby boys in the United Kingdom, with 11 O names in the top 300 for 2025, led by Oliver (#5). Of those, Ozzy is the fastest-growing, now 4.2 times as common as in 2020, while Oakley saw the largest increase in births, with 738 more babies receiving the name than in 2020. Omar (#169) is one of two O names that reached their highest ranks on record in 2025.