Franz Gerhard Wegeler (22 August 1765 - 7 May 1848) was a German physician from Bonn, who was a childhood friend of Ludwig van Beethoven. He was the father of historian Julius Stephan Wegeler (1807-1883).
He studied medicine at the Universities of Bonn and Vienna. After finishing his studies in Austria, he returned to Bonn, where he became a tenured professor of legal medicine and obstetrics (1789). In 1794 he fled Bonn during the French Revolutionary Wars, returning to Vienna, where he renewed his friendship with Beethoven. After spending two years in Vienna, he moved back to Bonn as an instructor and a general practitioner of medicine.
In 1807 he relocated to Koblenz, where he joined the Prussian civil service and attained several prestigious awards.
Wegeler was a Freemason; Beethoven corresponded with him on the subject of Beethoven's music (not masonic music) being used in lodge ceremonies. Beethoven offered to compose a better piece than he had heard was being used.
A distinguished doctor, Wegeler is remembered for his 1838 biography of Beethoven (Biographische Notizen über Ludwig van Beethoven), being published with composer Ferdinand Ries (1784-1838) eleven years after Beethoven's death. Historians consider these memoirs to be an important and reliable source of information in regards to the life of the great composer.