Isao is a very rare variant of Isai that was most common in the 1920s and has all but disappeared.
Isao is a boy name. It last appears in U.S. records in 2016. Isao first appears in 1915 and peaked in 1925 (20 births).
| Year | U.S. births | U.S. + territories | Rank |
|---|---|---|---|
| 2016 | 5 | 5 | #12,965 |
| 1944 | 5 | — | #3,650 |
| 1938 | 7 | — | #3,012 |
| 1935 | 5 | — | #3,908 |
| 1934 | 5 | — | #3,918 |
| 1933 | 6 | — | #3,452 |
| 1932 | 6 | — | #3,558 |
| 1930 | 9 | — | #2,879 |
| 1929 | 10 | — | #2,680 |
| 1928 | 9 | — | #2,945 |
| 1927 | 9 | — | #3,020 |
| 1926 | 12 | — | #2,488 |
| 1925 | 20 | — | #1,771 |
| 1924 | 13 | — | #2,404 |
| 1923 | 14 | — | #2,275 |
| 1922 | 18 | — | #1,925 |
| 1921 | 15 | — | #2,204 |
| 1920 | 8 | — | #3,348 |
| 1919 | 19 | — | #1,778 |
| 1918 | 10 | — | #2,780 |
| 1917 | 18 | — | #1,779 |
| 1916 | 11 | — | #2,460 |
| 1915 | 12 | — | #2,239 |