Prajapati (Sanskrit: प्रजापति, lit. 'Lord of the people', IAST: Prajāpati) is a Vedic deity of Hinduism. He is later identified with Brahma, the creator god.

Prajapati is a form of the creator-god Brahma, but the name is also the name of many different gods, in many Hindu scriptures, ranging from the creator god Brahma to being the same as one of the following deities: Vishvakarma, Agni, Indra, Daksha, and many others, because of the diverse Hindu cosmology. In classical and medieval era literature, Prajapati is the metaphysical concept called Brahman as Prajapati-Brahman, and Brahman is the primordial matter that made Prajapati.

Prajapati (Sanskrit: प्रजापति) is a compound of "praja" (creation, procreative powers) and "pati" (lord, master). The term means "lord of creatures", or "lord of all born beings". In the later Vedic texts, Prajapati is a distinct Vedic deity, but whose significance diminishes. Later, the term is synonymous with other gods, particularly Brahma. Still later, the term evolves to mean any divine, semi-divine or human sages who create something new.

The origins of Prajapati are unclear. He appears late in the Vedic layer of texts, and the hymns that mention him provide different cosmological theories in different chapters. He is missing from the Samhita layer of Vedic literature, conceived in the Brahmana layer, states Jan Gonda. Prajapati is younger than Savitr, and the word was originally an epithet for the sun. His profile gradually rises in the Vedas, peaking within the Brahmanas. Scholars such as Renou, Keith and Bhattacharji posit Prajapati originated as an abstract or semi-abstract deity in the later Vedic milieu as speculations evolved from the archaic to more learned speculations.

A similarity between Prajapati (and related figures in Hindu mythology) and Phanes, also named as Protogonus (Ancient Greek: Πρωτογόνος, literally "first-born") of the Greco-Roman mythology has been proposed:

Phanes is the Classical mythology equivalent of the Hindu god Brahma's Prajapati form in several ways: he is the first god born from a cosmic egg, he is the creator of the universe, and in the figure of Phanes— worshippers participate in his birth, death, rebirth, redeath.

— Kate Alsobrook, The Beginning of Time: Hindu Greco-Roman Theogonies and Poetics

According to Robert Graves, the name of /PRA-JĀ[N]-pati/ ('progeny-potentate') is etymologically equivalent to that of the oracular god Phanes at Colophon (according to Macrobius), namely /prōtogonos/. The cosmic egg concept linked to Prajapati and Phanes is common in many parts of the world, states David Leeming, which appears in later Greco-Roman worship in Greece and Rome.