The Positive Organ Company (also known as Casson's Patent Organ Co Ltd and Positive Organ Company (1922) Ltd but often referred to as Casson Positive) was an English pipe organ maker, established in London in 1898 by Thomas Casson, although with some earlier antecedents. The firm was best known for small, one-manual organs, which were able to be moved about. It ceased trading in 1941, but the name was revived in 2020 with a new, unrelated organ builder.