| Tacita | | - | Ancient Roman | |
| Tacitus | | - | Ancient Roman | |
| Taliesin | | tal-ee-ES-in (Welsh) | Welsh, Arthurian Romance | |
| Tarquinius | | - | Ancient Roman | |
| Tatiana | | tah-TYAH-nah (Russian, Polish, Spanish, Italian), TAH-tee-ah-nah (Finnish), ta-tee-AN-ə (English), ta-TYAN-ə (English) | Russian, Slovak, Bulgarian, Romanian, Polish, Greek, Georgian, Spanish, Portuguese, Italian, Finnish | |
| Tatianus | | - | Ancient Roman | |
| Tatius | | - | Roman Mythology, Ancient Roman | |
| Teodor | | te-AW-dawr (Polish), TE-o-dor (Croatian) | Swedish, Norwegian, Danish, Romanian, Czech, Slovak, Polish, Serbian, Croatian, Slovene, Hungarian, | |
| Teodora | | te-o-DAW-rah (Italian), te-o-DHO-rah (Spanish), te-aw-DAW-rah (Polish) | Italian, Spanish, Portuguese, Swedish, Romanian, Polish, Bulgarian, Macedonian, Serbian | |
| Terentius | | - | Ancient Roman | |
| Tereza | | te-REZ-ah (Romanian) | Czech, Portuguese (Brazilian), Bulgarian, Romanian | |
| Terminus | | - | Roman Mythology | |
| Tertius | | TUR-shəs (English) | Ancient Roman | |
| Theodor | | - | German, Swedish, Norwegian, Danish, Czech, Romanian | |
| Therasia | | - | Late Roman | |