| FULL FORMS |
| DUTCH: Wilhelmus, Willem |
| GERMAN: Wilhelm |
|
| EQUIVALENTS |
| ANCIENT GERMANIC: Wilhelm, Willahelm |
| BRETON: Gwilherm |
| CATALAN: Guillem |
| CROATIAN: Vilim, Vilko |
| CZECH: Vilém |
| DANISH: Vilhelm |
| DUTCH: Jelle, Pim, Wil, Willy, Wim |
| ENGLISH: Bill, Liam, Wil, Will, William, Willie, Willy |
| ESPERANTO: Vilĉjo, Vilhelmo |
| ESTONIAN: Villem |
| FINNISH: Jami, Vilhelm, Vilhelmi, Vilho, Vili, Viljami, Viljo, Ville |
| FRENCH: Guillaume |
| GERMAN: Willi, Willy, Wim |
| HUNGARIAN: Vili, Vilmos |
| ICELANDIC: Vilhjálmur |
| IRISH: Liam, Uilleag, Uilliam, Ulick |
| ITALIAN: Guglielmo |
| LATVIAN: Vilhelms, Vilis |
| LIMBURGISH: Wöllem, Wullem, Wum |
| LITHUANIAN: Vilhelmas |
| MANX: Illiam |
| MAORI: Wiremu |
| MEDIEVAL ENGLISH: Wilmot |
| NORWEGIAN: Vilhelm |
| POLISH: Wilhelm |
| PORTUGUESE: Guilherme |
| SCOTTISH: Uilleam |
| SLOVAK: Viliam |
| SLOVENE: Vili, Viljem, Vilko |
| SPANISH: Guillermo |
| SWEDISH: Vilhelm, Ville |
| WELSH: Gwil, Gwilim, Gwillym, Gwilym |
|
| DIMINUTIVES AND SHORT FORMS |
| ENGLISH: Billie, Billy |
| MEDIEVAL ENGLISH: Wilkin, Wilky |
|
| FEMININE FORMS |
| CROATIAN: Vilma |
| CZECH: Vilma |
| DUTCH: Elma, Helma, Mien, Mina, Wil, Wilhelmina, Willemijn, Willemina, Willy, Wilma |
| ENGLISH: Mina, Minnie, Velma, Wilhelmina, Willa, Wilma |
| FINNISH: Helmi, Iina, Miina, Mimmi, Minna, Vilhelmiina, Vilma |
| GERMAN: Elma, Helma, Helmine, Minna, Vilma, Wilhelmina, Wilhelmine, Wilma |
| HUNGARIAN: Vilma |
| LIMBURGISH: Mien, Mina |
| LITHUANIAN: Vilhelmina |
| PORTUGUESE: Vilma |
| SLOVAK: Vilma |
| SPANISH: Vilma |
| SWEDISH: Helmi, Mimmi, Minna, Vilhelmina, Vilma |
|
| OTHER FORMS |
| ENGLISH: Liam, Wilkie, Willis, Wilson |
|
