Could Sienna be the perfect name for your baby girl? The baby girl name Sienna is 6 letters long, and contains 3 vowel(s) and 3 consonant(s). Sienna is a baby girl name that starts with the letter S and ends in the letter A. The baby girl name Sienna has a popularity of 87% and is ranked 135 in the list of top 1000 most popular baby girl names. If Sienna isn't the ideal name for your baby girl then take a look here for some randomly generated names. Hopefully you'll find a more suitable first name for your baby girl than Sienna!