Io is a very rare name used for both girls and boys that peaked in 2022 and has grown less common since.
Io is predominantly a girl name. In 2025 it ranked #15,815 among girls (5) and #12,744 among boys (5) — overall #16,481 across all names. The charts below show girls and boys separately.
| Year | U.S. births | U.S. + territories | ♀ Rank | ♂ Rank |
|---|---|---|---|---|
| 2025 | 10 | 10 | #15,815 | #12,744 |
| 2023 | 15 | 15 | #9,881 | #12,957 |
| 2022 | 24 | 24 | #6,553 | #11,403 |
| 2021 | 15 | 15 | #7,407 | — |
| 2020 | 18 | 18 | #9,177 | #9,954 |
| 2019 | 6 | 6 | #14,487 | — |
| 2018 | 11 | 11 | #9,413 | — |
| 2017 | 7 | 7 | #13,254 | — |
| 2016 | 16 | 16 | #7,383 | — |
| 2015 | 11 | 11 | #17,496 | #11,219 |
| 2014 | 19 | 19 | #9,193 | #10,044 |
| 2013 | 12 | 12 | #9,241 | — |
| 2012 | 12 | 12 | #9,313 | — |
| 2011 | 9 | 9 | #11,548 | — |
| 2010 | 6 | 6 | #15,703 | — |
| 2009 | 8 | 8 | #12,903 | — |
| 2008 | 5 | 5 | #18,588 | — |
| 2007 | 5 | 5 | #18,697 | — |
| 2006 | 5 | 5 | #18,222 | — |
| 2004 | 7 | 7 | #13,277 | — |
| 2000 | 5 | 5 | #15,968 | — |