| Illud | Strong and courageous |
| Ilud | Strong and powerful |
| Ilvetos | Strong and victorious |
| Ilvveto | Strong and victorious |
| Imbicatos | Strong and unyielding |
| Immin | Strong and steadfast |
| Immine | Derived from Old English, possibly meaning 'immortal' or 'eternal' |
| Indulf | Old English name, possibly meaning 'ruler of the people' or 'leader' |
| Inee | Possibly derived from Old English, meaning 'chaste' or 'pure' |
| Ingeld | Old English name, possibly meaning 'bright battle' or 'shining warrior' |
| Ingeler | Derived from Old English, possibly meaning 'bright spear' or 'shining warrior' |
| Ingham | Old English name, possibly meaning 'home of the family' or 'homestead' |
| Ingilram | Derived from Old English, possibly meaning 'bright fame' or 'shining glory' |
| Ingin | Possibly derived from Old English, meaning 'bright' or 'shining' |
| Inguburh | Old English name, possibly meaning 'bright fortress' or 'shining stronghold' |
| Ingui | Derived from Old English, possibly meaning 'bright' or 'shining' |
| Ingulf | A name meaning a brave leader. |
| Ingulph | Old English name, possibly meaning 'bright wolf' or 'shining warrior' |
| Inguo | Possibly derived from Old English, meaning 'bright' or 'shining' |
| Ingwald | Derived from Old English, possibly meaning 'bright ruler' or 'shining leader' |
| Ingweald | Old English name, possibly meaning 'bright ruler' or 'shining leader' |
| Ingwulf | Derived from Old English, possibly meaning 'bright wolf' or 'shining warrior' |
| Inprimis | Latin name, meaning 'first of all' or 'most important' |
| Instio | Possibly derived from Old English, meaning 'instructor' or 'teacher' |
| Inwaer | Old English name, possibly meaning 'in war' or 'warrior' |
| Ioco | Possibly derived from Old English, meaning 'joy' or 'happiness' |
| Iocyn | Derived from Old Welsh, possibly meaning 'son of joy' or 'happy child' |
| Iohannes | God is gracious |
| Iordanus | Descended from the mountain |
| Ioruert | A name meaning a fair lord. |
| Iouanaul | God is gracious |
| Iovenali | A name meaning youthful one. |
| Ipa | A name meaning a peaceful soul. |
| Ipela | A name meaning to be joyful or happy. |
| Ippa | A name meaning a small, humble gift. |
| Irgen | A name meaning a noble, strong leader. |
| Irminric | A name meaning a powerful universe. |
| Irom | A name meaning a strong, iron spirit. |
| Ironside | Strong and steadfast |
| Isaacs | A name meaning one who will laugh. |