Over the past 110 years, 655 girls and 10 733 boys have been named Theo. The name Theo ranks 4429th in the United States among the most common names for girls. For the first time more than ten times newborns were named Theo in 1910. The peak of popularity of the name Theo 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.