Genitive Case (-in, -ın, -un, -ün) in Turkish

The Turkish Genitive Case (Tamlayan Durumu or İlgi Hali) uses the 4-way suffix -(n)In (-ın, -in, -un, -ün, with buffer n after vowel stems). Its primary purpose is to mark the possessor in a definite possessive compound (Belirtili İsim Tamlaması).

In Turkish, a possessive relationship is marked on both words: the possessor takes the genitive suffix, and the possessed noun takes the possessive suffix: öğrencinin çantası* (the student's bag), evin kapısı (the door of the house), İstanbul'un havası (Istanbul's weather). Stems ending in p, ç, t, k soften before the genitive (kitap → kitabın, çocuk → çocuğun*).

Pronoun forms have slight irregularities: ben → benim (my/mine, using -im instead of -in), sen → senin (your/yours), o → onun (his/her/its), biz → bizim (our/ours, using -im), siz → sizin (your/yours), onlar → onların (their/theirs). The genitive is also used before postpositions like için (for), gibi (like), and kadar (as much as) when preceded by personal and demonstrative pronouns (benim için = for me, onun gibi = like him).

Foreign learners frequently forget that Turkish requires double-marking, incorrectly saying öğrenci çanta or Ahmet araba instead of Ahmet'in arabası.