| Jacinto | | hah-THEEN-to (Spanish), hah-SEEN-to (Latin American Spanish) | Spanish, Portuguese | |
| Jaime (1) | | HIE-me (Spanish), ZHIEM (Portuguese) | Spanish, Portuguese | |
| Jaqueline | | JAK-ə-leen (English), JAK-ə-lin (English) | English (Modern), Portuguese (Brazilian) | |
| JerÓNimo | | he-RO-nee-mo (Spanish) | Spanish, Portuguese | |
| JerÔNimo | | - | Portuguese (Brazilian) | |
| Jeremias | | ye-re-MEE-ahs (German), YE-re-mee-ahs (Finnish) | German, Portuguese, Finnish | |
| Jessica | | JES-i-kə (English) | English, French, German, Swedish, Norwegian, Danish, Italian, Spanish, Portuguese | |
| JoÃO | | ZHWOWN, zhoo-OWN | Portuguese | |
| JoÃOzinho | | - | Portuguese | |
| Joana | | - | Portuguese, Catalan | |
| Joaninha | | - | Portuguese | |
| Joaquim | | - | Portuguese, Catalan | |
| Joel | | JOL (English), JO-əl (English), ho-EL (Spanish), zhoo-EL (Portuguese), YO-el (Swedish, Finnish) | English, Spanish, Portuguese, Swedish, Finnish, Biblical | |
| JordÃO | | - | Portuguese | |
| Jordana | | hor-DAH-nah (Spanish), jawr-DAN-ə (English) | Spanish, Portuguese, Macedonian, English (Rare) | |