Bistam or Vistahm (also transilterated Wistaxm, ), was a Parthian dynast of the Ispahbudhan house, and maternal uncle of the Sasanian shah of Persia, Khosrau II (reigned 591–628). Vistahm helped Khosrau regain his throne after the rebellion of Bahram Chobin, but later led a revolt himself, which encompassed the entire Iranian East before being suppressed.