Ashsha (Avestan: 𐬀𐬴𐬀, aṣ̌a) is a fundamental concept in Zoroastrianism, representing truth, righteousness, cosmic order, and the divine law that governs the universe. It is one of the most important theological and ethical principles in the religion, often contrasted with its opposite, druj (falsehood, disorder).
In the Gathas, the oldest texts of Zoroastrianism attributed to the prophet Zarathushtra (Zoroaster), Ashsha is closely associated with Ahura Mazda, the Wise Lord, embodying the divine order that creation follows. It encompasses not only physical order (like the regular movement of celestial bodies and the changing seasons) but also moral and social order. Adherents strive to live in accordance with Ashsha through good thoughts, words, and deeds, thereby contributing to the progress of the world towards its ultimate perfection (Frashokereti).
Ashsha is also personified as one of the Amesha Spentas (Bounteous Immortals), specifically Asha Vahishta ("Best Truth" or "Excellent Righteousness"), who is associated with fire, light, and the spiritual path to righteousness. The reverence for fire in Zoroastrianism is partly due to its connection with Asha Vahishta, symbolizing purity and truth. Living according to Ashsha is crucial for an individual's spiritual advancement and for the eventual triumph of good over evil in the cosmos.