| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 541 | Ives | German | Variant of Ivo: Yew. Introduced into Britain during the Norman Conquest. | M | |
| 542 | Ivo | German | Yew. Introduced into Britain during the Norman Conquest. | M | |
| 543 | Izaak | German | Laughter. | M | |
| 544 | Jaecar | German | Hunter. | M | |
| 545 | Jakob | German | German form of Jacob. | M | |
| 546 | Jansen | German | Variant of the Hebrew John 'Jehovah has been gracious; has shown favor.'. | M | |
| 547 | Jantis | German | Sharp spear. | M | |
| 548 | Jarman | German | A German. | M | |
| 549 | Jarmann | German | A German. | M | |
| 550 | Jarvis | German | Spear. Servant. Variant of Gervase. | M | |
| 551 | Jay | German | Swift. | M | |
| 552 | Jaye | German | Swift. | M | |
| 553 | Jeffery | German | Derived from one of three Old German names, meaning district, traveler, or peaceful pledge. Famous bearer: Geoffrey Plantagenet was father to King Henry II; Geoffrey Cbaucer wrote 'The Canterbury Tales'. | M | |
| 554 | Jeffrey | German | Derived from one of three Old German names, meaning district, traveler, or peaceful pledge. Famous bearer: Geoffrey Plantagenet was father to King Henry II; Geoffrey Cbaucer wrote 'The Canterbury Tales'. | M | |
| 555 | Jocelyn | German | One of the Goths. Introduced into Britam as a masculine name during the Norman Conquest, Jocelyn was adopted as a feminine first name in the early 20th century. | M | |
| 556 | Johan | German | German form of John. | M | |
| 557 | Johann | German | Variant of the Hebrew John 'Jehovah has been gracious; has shown favor.'. | M | |
| 558 | Johannes | German | German form of John. | M | |
| 559 | Joscelin | German | Variant of Jocelyn: One of the Goths'. Introduced into Britam as a masculine name during the Norman Conquest, Jocelyn was adopted as a feminine first name in the early 20th century. | M | |
| 560 | Josef | German | German form of Joseph. | M | |