Iyers (ajːɐr) (also spelt as Ayyar, Aiyar, Ayer, or Aiyer) are an ethnoreligious community of Tamil-speaking Hindu Brahmins. Most Iyers are followers of the Advaita philosophy propounded by Adi Shankara and adhere to the Smarta tradition. This is in contrast to the Iyengar community, who are adherents of Sri Vaishnavism. The Iyers and the Iyengars are together referred to as Tamil Brahmins. The majority of Iyers reside in Tamil Nadu, India.
Iyers are further divided into various denominations based on traditional and regional differences. Like all Brahmins, they are also classified based on their gotra, or patrilineal descent, and the Veda that they follow. They fall under the Pancha Dravida Brahmana classification of Brahmins in India.
Apart from the prevalent practice of using the title "Iyer" as surname, Iyers also commonly use other surnames, such as Sāstri or Bhattar.
Iyer (ஐயர், aɪjəɾ) has several meanings in Tamil and other Dravidian languages, often referring to a respectable person. The Dravidian Etymological Dictionary lists various meanings for the term such as "father, sage, priest, teacher, brahman, superior person, master, king" with cognates such as tamayan meaning "elder brother" and simply ai "lord, master, husband, king, guru, priest, teacher, father". Linguistic sources often derive the words Ayya, Ayira/Ayyira as Prakrit versions of the Sanskrit word Aryā which means 'noble'.
In ancient times, Iyers were also called Anthanar or Pārppān, though the usage of the word Pārppān is considered derogatory in modern times. Until recent times, Kerala Iyers were called Pattars. Like the term pārppān, the word Pattar too is considered derogatory.
Today, Iyers live all over South India, but an overwhelming majority of Iyers continue to thrive in Tamil Nadu. Tamil Brahmins form an estimated less than 3 per cent of the state's total population and are distributed all over the state. However, accurate statistics on the population of the Iyer community are unavailable.