"This is my uncle who is a vegetarian."

Translation: Αυτός είναι ο θείος μου ο οποίος είναι χορτοφάγος.

[Jon345104]

Getting confused this who is ο οποίος last who was του οποίου

[D_..]

It really is who = ο οποίος, whose = του οποίου and whom = τον οποίο. Consider how the pronoun shows the subject/predicate, possession or the object in the following examples:
This is my uncle who is a vegetarian. - Αυτός είναι ο θείος μου ο οποίος είναι χορτοφάγος. vs
This is my uncle whose car I borrowed. - Αυτός είναι ο θείος μου του οποίου το αυτοκίνητο δανείστηκα. vs
This is my uncle whom I love. - Αυτός είναι ο θείος μου τον οποίο αγαπώ.

[2Dzs1]

Τον οποιο or τον οποιον?

[Jon345104]

Thanks, that's helped clarify tthings

[LaraineCic]

That is helpful. Thank you

[MaggieHyam]

thank you that really helps

[beanzchica]

Why isn't "που" accepted, since it is defined as "that / where / who"?

[troll1995]

Αυτός είναι ο θείος μου που είναι χορτοφάγος is already accepted. Maybe there was some other mistake?