The Caslon type foundry was a type foundry in London which cast and sold metal type. It was founded by the punchcutter and typefounder William Caslon I, probably in 1720. For most of its history it was based at Chiswell Street, Islington, was the oldest type foundry in London, and the most prestigious. In the nineteenth century, the company established a division selling printing equipment. This section of the company continues to operate as of 2021, and is now branded Caslon Ltd. and based in St. Albans. The type foundry section of the company was bought by Stephenson Blake in 1937.