| Gabari | 2 |
| Gabarra | 1 |
| Gabarri | 1 |
| Gabas | 22 |
| Gabasa | 13 |
| Gabilan | 1 |
| Gainza | 4 |
| Galar | 4 |
| Galarza | 31 |
| Galban | 7 |
| Galdeano | 3 |
| Gale | 2 |
| Galilea | 1 |
| Galmate | 1 |
| Gallart | 3 |
| Gallipienzo | 10 |
| Gallues | 17 |
| Gamboa | 1 |
| Gambra | 2 |
| Gamio | 5 |
| Ganuza | 2 |
| Garaci | 2 |
| Garamendi | 20 |
| Garate | 3 |
| Garayo | 137 |
| Garayoa | 44 |
| Garces | 229 |
| Garcia | 543 |
| Garde | 79 |
| Garin | 19 |
| Garos | 2 |
| Garralda | 67 |
| Garraza | 16 |
| Garrero | 2 |
| Garrido | 1 |
| Garro | 22 |
| Garulo | 3 |
| Gasa | 1 |
| Gascon | 2 |
| Gascue | 2 |
| Gasos | 1 |
| Gaspar | 2 |
| Gastan | 2 |
| Gastes | 1 |
| Gaston | 6 |
| Gazpio | 2 |
| Geliz | 4 |
| Gil | 110 |
| Gimenez | 1 |
| Gimeno | 1 |
| Ginto | 7 |
| Giron | 26 |
| Girona | 1 |
| Glaria | 1 |
| Godet | 3 |
| Goicoechea | 4 |
| Goldaracena | 4 |
| Goldaraz | 1 |
| Golinat | 1 |
| Gollarte | 1 |
| Gomara | 1 |
| Gomez | 33 |
| Gongora | 1 |
| Goņi | 123 |
| Gonzalez | 34 |
| Gonzalo | 1 |
| Gorge | 1 |
| Gorria | 8 |
| Gorricho | 9 |
| Gorriz | 217 |
| Gortari | 4 |
| Goyara | 3 |
| Goyena | 17 |
| Goyeneche | 38 |
| Graci ? | 1 |
| Gracia | 10 |
| Grasa | 2 |
| Gravalos | 3 |
| Gregorio | 3 |
| Greņo | 2 |
| Grez | 11 |
| Griņac | 7 |
| Guallar | 4 |
| Guallart | 4 |
| Guaz | 1 |
| Guelbenzu | 25 |
| Guembe | 6 |
| Guendulain | 1 |
| Guerrero | 24 |
| Güesa | 111 |
| Guillen | 5 |
| Guinda | 66 |
| Guindano | 15 |
| Gurpegui | 4 |
| Gurpide | 14 |
| Gurrea | 7 |
| Gurria | 9 |
| Gurricho | 14 |
| Gutia | 1 |
| Gutierrez | 4 |
| Ibaņez | 240 |
| Ibarra | 9 |
| Ibero | 16 |
| Ibiricu | 9 |
| Iciz | 82 |
| Icurgui | 4 |
| Idiarte | 1 |
| Idoate | 1 |
| Idocin | 5 |
| Iduate | 1 |
| Igal | 15 |
| Iglesia | 5 |
| Iglesias | 2 |
| Iguacel | 3 |
| Igual | 2 |
| Iguaz | 6 |
| Igurza | 1 |
| Ijue | 1 |
| Ildueta | 3 |
| Ilibarren | 3 |
| Ilincheta | 7 |
| Ilisarri | 1 |
| Ilundain | 4 |
| Imbers | 22 |
| Imbuluzqueta | 4 |
| Imirizaldu | 2 |
| Imizcoz | 3 |
| Inda | 8 |
| Indurain | 78 |
| Iņigo | 1 |
| Iņiguez | 100 |
| Insausti | 5 |
| Ipas | 1 |
| Iracheta | 9 |
| Iragui | 4 |
| Iraizoz | 42 |
| Iraņeta | 18 |
| Irarregui | 1 |
| Irarri | 2 |
| Iriart | 2 |
| Iriarte | 136 |
| Iribarren | 152 |
| Iribas | 2 |
| Irigoyen | 38 |
| Iriguibel | 1 |
| Irisarri | 8 |
| Iriso | 4 |
| Irizalde | 1 |
| Irorozqui | 1 |
| Iroz | 9 |
| Irurita | 14 |
| Irurozqui | 45 |
| Isarri | 1 |
| Isidro | 1 |
| Iso | 415 |
| Isturiz | 7 |
| Ito | 1 |
| Itoiz | 48 |
| Iturbide | 8 |
| Iture | 1 |
| Iturmendi | 2 |
| Iturralde | 31 |
| Iturri | 9 |
| Iturria | 52 |
| Iturrioz | 1 |
| Izaga | 2 |
| Izal | 7 |
| Izalzu | 1 |
| Izco | 55 |
| Iziz | 6 |
| Izquierdo | 7 |
| Izquieta | 41 |
| Izu | 9 |
| Izura | 6 |
| Jabala | 6 |
| Jaca | 56 |
| Jacoisti | 8 |
| Jacoiz | 42 |
| Jaume | 3 |
| Jara | 2 |
| Jarri | 1 |
| Jasa | 1 |
| Jaso | 2 |
| Jaunsaras | 5 |
| Jauregui | 12 |
| Javala | 16 |
| Javerri | 5 |
| Javier | 4 |
| Jaz | 1 |
| Jimenez | 226 |
| Jimeno | 40 |
| Jinto | 7 |
| Jordan | 26 |
| Jorge | 1 |
| Josue | 2 |
| Jovesano | 1 |
| Jovican | 1 |
| Juan | 4 |
| Juangorri | 2 |
| Juanto | 29 |
| Juarez | 1 |
| Jubilar | 2 |
| Jugand | 4 |
| Jurico | 15 |
| Juries | 1 |
| Jurio | 4 |
| Justa | 6 |
| Juste | 10 |
| Jusue | 3 |
