The National Youth Theatre of Great Britain (NYT) is a youth theatre and registered charity in London. Its aim is to develop and nurture young people through creative arts and theatrical productions. Founded in 1956 as the world's first youth theatre, the NYT has built a reputation for producing actors such as Daniel Craig, Daniel Day-Lewis, Timothy Dalton, Chiwetel Ejiofor, Colin Firth, Derek Jacobi, Ben Kingsley, Ian McShane, Helen Mirren, Lysette Anthony, Rosamund Pike, Regé-Jean Page and Kate Winslet, among numerous others.

The NYT holds annual acting auditions and technical theatre interviews around the United Kingdom, receiving an average of over 5,000 applicants. Currently, around 500 places are offered on summer acting and technical courses (costume, lighting and sound, scenery and prop making, and stage management), which offer participants NYT membership upon completion. Members are then eligible to audition for the company's productions, which are staged in London's West End, around the country, and internationally.

NYT members staged the Olympic and Paralympic Team Welcome Ceremonies at the 2012 Summer Olympics in London. In 2013, the NYT raised their age limit to 25 and introduced a new summer course called Epic Stages to cater for performance and production talent between ages 18–25. In summer 2014, members staged the Village Ceremonies at the 2014 Commonwealth Games in Glasgow.

In 2018 Akshay Sharan won Best Actor in a Play at The Stage Debut Awards for his lead performance in The Reluctant Fundamentalist, Mohsin Hamid's Manbooker Prize shortlisted novel, which National Youth Theatre commissioned Stephanie Street to adapt and which they produced to critical acclaim at the Finborough Theatre, Yard Theatre and Edinburgh Festival,