The prestigious festival dedicated to the works of Richard Wagner takes place in the southern town of Bayreuth, the composer's spiritual home, each year.
Siemens became involved four years ago hosting public screenings of performances which were also broadcast on the internet on "Siemens Festival Night."
A company spokesman said the events had enjoyed success but "the baby has grown up and learned to walk on its own, and now we wish to pursue other projects."
The contribution of Siemens, the festival's main financial sponsor along with German car maker Audi, stands at just less than €1 million ($1.4 million) a year.
Festival directors, Wagner's great-granddaughters Katharina Wagner, 32, and her half-sister Eva Wagner-Pasquier, 65, "were informed of our decision several months ago", the spokesman said.
The organizers could not be contacted for comment.