Otto III (11 February 1261 – 9 November 1312), a member of the Wittelsbach dynasty, was the Duke of Lower Bavaria from 1290 to 1312 and the King of Hungary and Croatia between 1305 and 1307.

[2] Since the Habsburg Albert I of Germany was blocking the way through Austria, Otto disguised himself as a merchant, and reached Buda in November 1305.

In June 1307, Duke Otto III visited the powerful Voivode of Transylvania, Ladislaus Kán, but the latter imprisoned him.

[3] On 10 October 1307, the magnates presented at the assembly in Rákos proclaimed Charles king, but the most powerful aristocrats (Matthew III Csák, Amadé Aba and Ladislaus Kán) ignored him as well.

Otto's involvement in Austrian and Hungarian affairs weakened his position in Bavaria and finally led to failure due to financial problems.