Joseph Willibrord Mähler (10 June 1778, Koblenz-Ehrenbreitstein – 20 June 1860, Vienna) was a German painter.
His parents were Franz Josef Mähler and Anna Johanna, née Vacano.
He first served an apprenticeship in Dresden with Anton Graff to become a painter and later on, he continued with his studies at the Academy of Fine Arts Vienna.
Mähler then decided to start a civil career and he became an officer of the secret service Geheime Kabinettskanzlei (secret chancellery) in Vienna.
Now, painting was just a hobby to him.
Mähler was introduced to Ludwig van Beethoven by Beethoven's school day friend Stephan von Breuning in the winter 1803/04.
He painted his first portrait of Beethoven, which shows three quarters of the composer's body in an Arcadian landscape, holding a lyre-guitar in his hand.
(Today, the painting is located in the Beethoven Memorial, the Pasqualati House in Vienna.) In the 19th century, this illustration – one of just a few depictions of Beethoven when he was young – mainly became famous due to a lithograph by Josef Kriehuber.
Around 1815, Mähler produced a series of portraits showing contemporary Viennese composers.
As written in the Allgemeine Musikzeitung (General music journal) in August 1815, "all of them distinguish themselves in a most creditable way through the effectual brush stroke, the descriptive resemblance and the distinctive expression of their soul".
A half length portrait of Beethoven was part of the series.
The painter created several versions of this portrait.