The Nikon FM is a 24 × 36 SLR camera manufactured between 1977 and 1982 by Nikon. It is the successor to the Nikkormat FT3 and uses the new AI (Aperture Index) light meter coupling system developed by Nikon. It is the first of a lineage of compact cameras (FM, FE, FM2, FE2, FA and FM3A) that will last until 2006.

The Nikon FM is distinguished from the very similar contemporary Nikon FE mainly by its mechanical shutter, usable without batteries at all speeds, and by the absence of automatic exposure mode with aperture priority. The exposure time can be set between 1 s and 1/1 000 s in full values, as well as in B mode.

The light measurement, of the center-weighted type, is done through the lens (TTL measurement).

The exposure setting is done using three LEDs (overexposure, correct exposure, and underexposure) that are visible on the right edge of the viewfinder. On the left edge, the selected exposure time is displayed. At the top of the viewfinder, the ADR window (for “Aperture Direct Readout”) allows for reading the selected aperture directly from the lens ring, if it is equipped with a suitable scale (small numbers on AI, AI-S, and AF lenses).