Nikonos Calypso is the name of a series of 35mm format cameras specifically designed for underwater photography launched by Nikon in 1963. The early Nikonos cameras were improvements of the Calypso camera, which was an original design by Jacques-Yves Cousteau and Belgian engineer Jean de Wouters . It was produced in France by La Spirotechnique (currently Aqua Lung) until the design was acquired by Nikon to become the Nikonos.

The Nikonos system was immensely popular with both amateur and professional underwater photographers. Its compact design, ease of use, and excellent optical quality set the standard for several decades of underwater imaging. Nikon ceased development and manufacture of new Nikonos cameras in 2001, but the camera remains popular, and there is a large and active secondary market.