The manufacturer with the most overall wins at the 24 Hours of Le Mans is Porsche.
Porsche has recorded 19 overall victories in the endurance classic, more than any other manufacturer. Its first win came in 1970 with the Porsche 917, driven by Hans Herrmann and Richard Attwood. Porsche’s record includes a remarkable seven consecutive victories from 1981 through 1987.
Audi ranks second with 13 overall wins, while Ferrari has 12 according to the current manufacturer statistics. Toyota has five overall victories, including its first in 2018. These totals refer to overall race wins, not victories in individual classes, where many manufacturers have accumulated separate records.
Another potential confusion involves teams. Joest Racing, which operated Porsche and Audi programs, has a major Le Mans record of its own. The question asks for the manufacturer, however, so the accepted answer is Porsche—not Joest Racing, Audi or Ferrari.