Sheffield Theatres has also won the Regional Theatre of the Year award for the third time
Sonia Friedman has been named Producer of the Year at The Stage Awards for the third year in a row.
Over the last 12 months, Friedman has produced Harry Potter and the Cursed Child, Dreamgirls and the West End production of Nice Fish.
Earlier this month, she was also named top of The Stage 100, the theatre industry power list.
On accepting the award at the ceremony, held at Theatre Royal, Drury Lane, Friedman said: "Right now theatre artists, the world is in crisis and this is our moment to make a difference.
"I feel a huge personal responsibility to do the best we can do. We are never going to stop, you'll have to cart me away in a coffin."
Sheffield Theatres won the award for Regional Theatre of the Year for the third time. This past year has seen the theatre host productions of Cuttin' It, Annie Get Your Gun and Show Boat.
Regent's Park Open Air Theatre has been recognised as London Theatre of the Year after staging productions of Running Wild and Jesus Christ Superstar. The latter will return to the theatre this summer, and Tyrone Huntley (who played Judas) will perform at the 17th Annual WhatsOnStage Awards in February.
King’s Cross Theatre, which over the last 12 months hosted the Donmar's Shakespeare Trilogy, Lazarus, In the Heights and The Railway Children won Theatre Building of the Year. The New Diorama Theatre Theatre won Fringe Theatre of the Year.
Elsewhere, Matthew Bourne's New Adventures won the International Award, theatre company Complicite won the Innovation Award, and Unsung Hero went to the Old Vic's stage door manager Ned Seago.
Regional Theatre of the Year
Sheffield Theatres
London Theatre of the Year
Regent’s Park Open Air Theatre
Fringe Theatre of the Year
New Diorama Theatre, London
Theatre Building of the Year
King’s Cross Theatre, London
Producer of the Year
Sonia Friedman Productions
School of the Year
Musical Theatre Academy, London
International Award
Matthew Bourne’s New Adventures
Sustainability Award
Tara Theatre, London
Innovation Award
Complicite
Unsung Hero
Ned Seago