The Indo-Iranian language group constitutes the easternmost extant branch of the Indo-European family of languages. It consists of four language groups: the Indo-Aryan, Iranian, Nuristani, and Dardic. The term Aryan languages is also used to refer to the Indo-Iranian languages . The speakers of the Proto-Indo-Iranian language, the hypothetical Proto-Indo-Iranians, are usually associated with the late 3rd millennium BC Sintashta-Petrovka culture of Central Asia. Their expansion is believed to have been connected with the invention of the chariot.
The contemporary Indo-Iranian languages form the largest sub-branch of Indo-European, with more than one billion speakers in total, stretching from Europe (Romani) and the Caucasus (Ossetian) to East India (Bengali and Assamese). SIL in a 2005 estimate counts a total of 308 varieties, the largest in terms of native speakers being Hindustani (Hindi and Urdu, ca. 540 million), Bengali (ca. 200 million), Punjabi (ca. 80 million), Marathi and Persian (ca. 70 million each), Gujarati (ca. 45 million), Pashto (40 million), Oriya (ca. 30 million), Kurdish and Sindhi (ca. 20 million each).

Subdivisions
Indo-European topics
Iranian Group:
Indo-Aryan Group:
Dardic languages (sometimes also classified as Indic):
Nuristani languages:

Eastern Iranian

• Northeastern
  
  
  
  • Avestan (extinct)
    Scythian (extinct)
    
    
    
    • Saka (extinct)
      Ossetian
      Sogdian (extinct)
      Yaghnobi
      Bactrian (extinct)
      Southeastern
      
      
      
      • Pashto
        Pamiri
        Western Iranian
        
        
        
        • Northwestern
          
          
          
          • Dari language of Zoroastrians
            Balochi
            Gilaki
            Kurdish
            Talysh
            Zazaki
            Southwestern ("Persid")
            
            
            
            • Old Persian (extinct)
              Middle Persian (extinct)
              New Persian
              
              
              
              • Tajik
                
                
                
                • Bukhori
                  Luri / Bakhtiari
                  Tat
                  Vedic Sanskrit
                  Sanskrit
                  Pāli
                  Central Zone
                  
                  
                  
                  • Hindustani
                    
                    
                    
                    • Hindi
                      Urdu
                      Romani/Romany
                      Eastern Zone (Magadhan Prakrit languages)
                      
                      
                      
                      • Angika
                        Assamese
                        Bengali
                        Bhojpuri
                        Magadhi
                        Maithili
                        Oriya
                        Northern Zone (Pahari languages)
                        
                        
                        
                        • Nepali
                          Northwestern Zone
                          
                          
                          
                          • Punjabi
                            Sindhi
                            Khojki
                            Kutchi
                            Rajasthani
                            Southern Zone
                            
                            
                            
                            • Dhivehi / Mahl
                              Sinhala
                              Western Zone
                              
                              
                              
                              • Gujarati
                                Konkani
                                Marathi
                                Dameli
                                Domaaki
                                Gawar-Bati
                                Kalsha-mun
                                Kashmiri
                                Khowar
                                Kohistani
                                Ningalami
                                Pashayi
                                Palula
                                Shina
                                Shumashti
                                Ashkunu (Ashkun)
                                Kamkata-viri (Bashgali)
                                Vasi-vari (Prasuni)
                                Tregami
                                Kalasha-ala (Waigali)