Arya Samaj (Aryan Society or Society of Nobles) is a Hindu reform movement in India that was founded by Swami Dayananda in 1875. He was a sannyasin (renouncer) who believed in the infallible authority of the Vedas. Dayananda advocated the doctrine of Karma and reincarnation, and emphasized the ideals of brahmacharya (chastity) and sanyasa (renunciation). Swami Dayanand and the Arya Samaj movement attracted a large number of followers in Haryana, including Lala Lajpat Rai, Sir Chhotu Ram and Seth Chhaju Ram.

The doctrines of the Samaj are summed up in Ten Principles:

1. God is the primary cause of all true science and of all that can be known through it.

2. God is Existent, Intelligent and Blissful. He is Formless, Almighty, Just, Merciful, Unborn, Infinite, Unchallengeable, Beginningless, Incomparable, the Support and Lord of all, Omniscient, Imperishable, Immortal, Fearless, Eternal, Holy and the Maker of the universe. To Him alone worship is due.

3. The Vedas are scriptures of true knowledge. It is the duty of all Aryas to read them, hear them being read and recite them to others.

4. All persons should be ready to accept the truth and give up untruth.

5. All action should be performed in conformity with Dharma, that is, after due consideration of the right and wrong.

6. The primary aim of the Arya Samaj is to do good for all, that is, promote physical, spiritual and social well-being.

7. All people should be treated with love, fairness and due regard for their merit.

8. One should aim at dispelling ignorance and promoting knowledge.

9. One should not only be content with one's own welfare, but should look for it in the welfare for others also.

10. One should regard oneself under restriction to follow altruistic rulings of society, while all should be free in following the rules of individual welfare.

Dayananda claimed to be rejecting all non-Vedic beliefs altogether. Hence the Arya Samaj unequivocally condemned idolatry, animal sacrifices, ancestor worship, pilgrimages, priest craft, offerings made in temples, the caste system, untouchability and child marriages, on the grounds that all these lacked Vedic sanction. It aimed to be a universal "church" based on the authority of the Vedas. Swami Dayananda stated that he wanted ‘to make the whole world Aryan’. That is, he wanted to develop a missionary Hinduism based on the universality of the Vedas.

To this end the Arya Samaj set up schools and missionary organizations, extending its activities outside India. It now has branches around the world. In comparison with India it has disproportionably many adherents in Surinam and the Netherlands among people of Indian ancestry.