Built by the Tunbridge Wells Corporation and designed by Percy Thomas and Ernest Prestwich, the Assembly Hall Theatre opened on 24 May 1939. Originally, the auditorium had a capacity of 822 on the ground floor, with a further 320 in the balcony. It was also equipped with a 22ft x 29ft cinema screen to allow films to be shown. It now seats up to 993 people, with 672 on the ground floor (373 in the stalls and 300 in tiered stalls) and 320 on the balcony (circle).
During the Second World War, the theatre was used for dances for troops, film shows and events to raise money for the war effort. By 2001, the theatre was attracting audiences of over 150,000 each year. The theatre was refurbished in 2001 with works including the provision of additional dressing rooms, remodelling the bar, repainting of the foyer and front of house areas, and new seating, air conditioning and other facilities.
closed again in August 2015 for a £1.5 million refurbishment. New tiered charcoal-coloured seating replaced the previous fixtures. The balcony seating was re-upholstered in the same hard-wearing material. Overheating was addressed and the
was redesigned in black, charcoal and gold.