Proto-Iranian, is the reconstructed proto-language of the Iranian languages branch of Indo-European language family. Its speakers, the hypothetical Proto-Iranians, are assumed to have lived in the early 2nd millennium BC, and are usually connected with the Proto-Indo-Iranians and early Andronovo archaeological horizon.

Proto-Iranian was a Satem language, likely removed less than two millennium from the late Proto-Indo-European language, and in turn removed less than a millennium from the Avesta language. It is the ancestor of the Iranian languages such as Persian, Sogdian, Zazaki, Mazandarani, Kurdish and others.

Proto-Indo-European and Indo-Iranian Phonological Correspondences

|-
| *p  

|-
| *bh 

|-
| *t  

|-
| *d  

|-
| *dh 

|-
| *k?  

|-
| *?  

|-
| *?h 

|-
| *k  

|-
| *g 

|-
| *gh 

|-
| *kw 

|-
| *gw 

|}