The Brihadaranyaka Upanishad (Sanskrit: बृहदारण्यक उपनिषद्, Bṛhadāraṇyaka Upaniṣad) is one of the Principal Upanishads and one of the first Upanishadic scriptures of Hinduism. A key scripture to various schools of Hinduism, the Brihadaranyaka Upanisad is tenth in the Muktikā or "canon of 108 Upanishads".

The Brihadaranyaka Upanishad is estimated to have been composed about 700 BCE, excluding some parts estimated to have been composed after the Chandogya Upanishad. The Sanskrit language text is contained within the Shatapatha Brahmana, which is itself a part of the Shukla Yajur Veda.

The Brihadaranyaka Upanishad is a treatise on Ātman (Soul, Self), includes passages on metaphysics, ethics and a yearning for knowledge that influenced various Indian religions, ancient and medieval scholars, and attracted secondary works such as those by Adi Shankara and Madhvacharya.

rihadaranyaka literally means "great wilderness or forest". The Brihadaranyaka Upanishad is credited to ancient sage Yajnavalkya, but likely refined by a number of ancient Vedic scholars. The Upanishad forms the last part, that is the fourteenth kānda of Śatapatha Brāhmana of "Śhukla Yajurveda".The Brihadaranyaka Upanishad has six adhyayas (chapters) in total. There are two major recensions for the text - the Madhyandina and the Kanva recensions. It includes three sections: Madhu kānda (the 4th and 5th chapter of the fourteenth kānda of Satapatha Brahmana), Muni kānda (or Yajnavalkya Kanda, the 6th and 7th chapter of 14th kānda of Satapatha Brahmana) and Khila kānda (the 8th and 9th chapter of the fourteenth kānda of Satapatha Brahmana).

The first and second chapters of the Upanishad's Madhu kānda consists of six brahmanas each, with varying number of hymns per brahmana. The first chapter of the Upanishad's Yajnavalkya kānda consists of nine brahmanams, while the second has six brahmanas. The Khila kānda of the Upanishad has fifteen brahmanas in its first chapter, and five brahmanas in the second chapter.