Castor is a contemporary art gallery founded in 2016, now based at the historic Holy Trinity, a Grade 2 listed church on Cloudesley Square, Islington.

Since inception Castor has focused on supporting emerging artists to realise ambitious presentations of their practice, often exploring social and personal narratives through sculpture, painting, video and installation. In recent years the gallery has worked with a number of estates and overlooked artists on survey exhibitions.

Holy Trinity was constructed between 1827 - 29 and designed by Charles Barry, who was chief architect for the Houses of Parliament. Castor at Holy Trinity is split between two space, the more intimate South gallery alongside the cavernous East gallery with pitched roof rising to 5.5 metres at its highest point, boosting over 1000 sq ft of exhibition space and sculpture garden.

Castor launched in 2016 in a basement space adjacent to Goldsmiths in New Cross with ten solo exhibitions in twelve months before operating from Resolution Way in Deptford between 2017 - 2022, where it continued to thrive within the South East London art scene. In 2022, Castor relocated to the heart of Fitzrovia, Central London where it operated until moving to its current space in April 2024.