The venue was packed for a performance of the Arthur Miller play Death of a Salesman.
The partial ceiling collapse happened above the circle and led to more than 1,000 people.
Ambassador Theater Group said: Pic We are sorry to confirm that at 8pm this evening during a performance at the Piccadilly Theater.
Performance The performance was immediately stopped and the theater safely evacuated.
“Five members of the audience sustained minor injuries and were taken to local hospitals.”
ATG said an investigation into the cause of the collapse.
Six years ago 76 people were injured when the ceiling collapsed at the nearby Apollo Theater.
The incident led to a call by the Westminster Council for theater owners to carry out thorough building checks.