Over the past 110 years, 197 283 boys and 196 girls have been named Leo. The name Leo ranks 175th in the United States among the most common names for boys. For the first time more than ten times newborns were named Leo in 1910. The peak of popularity of the name Leo came in the 1910s and 1920s. You can see absolute numbers and relative numbers on the chart. Indicators per 100K more accurately assess the popularity of the name.