Surnames Irwin – Isaksson
- Irwin (1,042)
- Irwin Biernacki (1)
- Irwine (2)
- Irwing (1)
- Irwins (1)
- Irwinsky (9)
- Iry (2)
- Isa (14)
- Isa-Yusuf (1)
- Isaac (548)
- Isaac-Obiefuna (1)
- Isaac-Perez (1)
- Isaachs (1)
- Isaachsen (1)
- Isaack (6)
- Isaacks (231)
- Isaackson (1)
- Isaacman (1)
- Isaacs (354)
- Isaacson (88)
- Isaags (1)
- Isaak (10)
- Isaako (1)
- Isaal (1)
- Isaaq (1)
- Isabel (17)
- Isabel Badillo (1)
- Isabeles (2)
- Isabell (45)
- Isabella (2)
- Isabelle (11)
- Isabelo (1)
- Isaboke (7)
- Isac (1)
- Isacheto (1)
- Isackes (2)
- Isacks (1)
- Isackson (1)
- Isacson (4)
- Isada (1)
- Isadore (29)
- Isaeff (1)
- Isagan (2)
- Isagba (2)
- Isaginges (1)
- Isaguirre (40)
- Isaguirrez (1)
- Isah (2)
- Isahac (3)
- Isaia (2)
- Isaiah (17)
- Isaias (17)
- Isaie (1)
- Isaila (1)
- Isais (60)
- Isais-Saavedra (1)
- Isaisas (1)
- Isaiz (7)
- Isak (3)
- Isakeit (1)
- Isakovic (1)
- Isakow (1)
- Isaksen (2)
- Isakson (20)
- Isaksson (3)