The British Interplanetary Society (BIS) is a London-based organization with an international membership of several thousand, formed in 1933 to promote the exploration and utilization of space.

In the 1930s, the BIS came up with plans for a manned lunar spacecraft, three decades before Apollo. In the late 1970s, it prepared a detailed design for a robot star-probe, Project Daedalus, to explore the system of Barnard's Star. It publishes the monthly magazine Spaceflight and a technical periodical Journal of the British Interplanetary Society.