Lilian Baylis (1874–1937) was an English theatrical producer and manager. She managed the Old Vic and Sadler's Wells theatres in London, and established an opera company, which became ENO, a theatre company, which evolved into the National Theatre, and a ballet company, which eventually became the Royal Ballet.

Born in London, her education was mainly in music, and she began performing and teaching music at an early age. She spent some years (1891–1898) in South Africa as a music and dance teacher. The other major influence in Baylis’s life was her aunt, Emma Cons, who was an associate of Octavia Hill and worked energetically to improve the quality of life for those living in London’s slums. Cons owned a lot of property in slum areas around Waterloo and believed that providing alternative forms of entertainment to the pub would benefit people in the area. She owned the Old Vic Theatre and began to put on popular shows with cheap refreshments. When Baylis returned from South Africa, she helped her aunt with the management of the Old Vic. Discovering that she had a natural aptitude for the business, she gradually took on more management duties until, on Cons’s death in 1912, she took over the Old Vic, which she ran until her own death in 1937.

While she shared her aunt’s passionate devotion to the poor, her approach to the programming at the Old Vic was different. She wanted to give her audience the very best in theatrical entertainment and believed this was opera and Shakespeare. Because this was all new to the people in Waterloo, she made sure that the opera was always sung in English.

In 1925, Baylis began a campaign to re-open the derelict Sadler's Wells Theatre in North London, something she finally achieved with a gala opening on 6 January 1931, launching the combined ‘Vic-Wells’ opera, ballet and drama companies, of which ENO is a direct descendant.

In 1937 Baylis died of a heart attack at the age of 63 but the principles on which her theatre companies were founded remain at the heart of ENO to this day. Most productions are sung in English and for every performance 500 tickets are available for £25 or less. Through an innovative artistic programme created by outstanding talent from across the arts and the work of ENO’s learning and participation team, ENO Baylis <internal link to ENO Baylis page>, ENO hopes to continue attracting newcomers to opera.