Johann Georg Hitler (baptised 28 February 1792 – 9 February 1857) was born to Stefan Hiedler (1762–1829) and Anna Maria Göschl (1760–1854). He was considered the officially accepted paternal grandfather of Adolf Hitler by the Third Reich. Whether Johann Georg was in fact Hitler's biological paternal grandfather is disputed by modern historians.
He was from Spital (part of Weitra), Austria, and made his living as a wandering journeyman miller.
In 1824, he married his first wife but she died in childbirth five months later.
In 1842, he married Maria Anna Schicklgruber and became the legal stepfather to her illegitimate five-year-old son, Alois. It was later claimed Johann Georg had fathered Alois prior to his marriage to Maria, although Alois had been declared illegitimate on his birth certificate and baptism papers; the claim that Johann Georg was the true father of Alois was not made after the marriage of Maria and Johann Georg, or, indeed, even during the lifetime of either of them.
In 1877, twenty years after the death of Johann Georg and almost thirty years after the death of Maria, Alois was legally declared to have been Johann Georg's son.
Accordingly, Johann Georg Hiedler is one of two people most cited by modern historians as having possibly been the actual paternal grandfather of Adolf Hitler. The other one is Johann Nepomuk Hiedler, the younger brother of Johann Georg.
In the 1950s, a third false claim that a Graz Jew by the name of Leopold Frankenberger was the paternal grandfather, but modern historians now have debunked this possibility as Jews were expelled from Graz in the fifteenth century and were not permitted to return until the 1860s, several decades after Alois was born.