The Philharmonia Orchestra is a British orchestra based in London. It was founded in 1945 by Walter Legge, a classical music record producer for EMI. Among the conductors who worked with the orchestra in its early years were Richard Strauss, Wilhelm Furtwängler and Arturo Toscanini; of the Philharmonia's younger conductors, the most important to its development was Herbert von Karajan who, though never formally chief conductor, was closely associated with the orchestra in the late 1940s and early 1950s. The Philharmonia became widely regarded as the finest of London's five symphony orchestras in its first two decades.

The Philharmonia has had many celebrated players in its ranks and has commissioned more than 100 compositions. It gives more than 160 concerts a year, tours widely, and from its inception has been known for its many recordings.