Vishtaspa (Vištāspa) is the Avestan-language name of a figure of Zoroastrian scripture and tradition, portrayed as an early follower of Zoroaster, and his patron, and instrumental in the diffusion of the prophet's message. Although Vishtaspa is not epigraphically attested, he is – like Zoroaster also – generally assumed to have been a historical figure, and – again, like Zoroaster – that figure is obscured by accretions from legend and myth.
In Zoroastrian tradition, which builds on allusions found in the Avesta, Vishtaspa is a righteous king who helped propagate and defend the faith. In the non-Zoroastrian Sistan cycle texts, Vishtaspa is a loathsome ruler who intentionally sends his eldest son to a certain death. In Greco-Roman literature, Zoroaster's patron was the pseudo-anonymous author of a set of prophecies written under his name.
Vishtaspa is referred to in the Gathas, the oldest texts of Zoroastrianism which were considered to have been composed by Zoroaster himself. In these hymns, the poet speaks of Vishtaspa as his ally (Yasna 46.14), follower of the path of Good Thought (Y. 51.16), and committed to spreading the prophet's message (Y. 51.16, 46.15, 53.2). In Yasna 28.1–28.7, Zoroaster appeals to Mazda for several boons, including the power to vanquish their foes for Vishtaspa and himself. Considered collectively, the Gathas celebrate Vishtaspa as the "patron of Zoroaster and the establisher of the first Zoroastrian community."