Gallery ONE opened its doors in 2015 as a private gallery for contemporary art, focusing on curatorial practices and showcasing Bulgarian contemporary art alongside established and emerging artists from around the world. On November 28, 2017, the gallery expanded with a second exhibition space at the corner of Ivan Vazov Street and 6th September Street in Sofia. The gallery's space, located in a 20th-century building in the heart of Sofia, was designed by architect Georgi Ovcharov and restored by CONA architects. On June 27, 2023, the gallery further expanded its activities by opening a new location at 1 Dyakon Ignatiy Street in Sofia, in a historically significant space - the old Bulgaria café from the early 20th century, spanning 300 square meters over two floors.