The Pentax LX is a 35mm single-lens reflex camera produced by Pentax in Japan. It was introduced in 1980 to commemorate the 60th anniversary of Asahi Optical Co., and was produced until 2001. It is the top-of-the-line professional, or "system", camera in the Pentax manual focus range, with manual and aperture priority automatic exposure modes and an advanced light metering system. The LX uses the K mount, which is the Pentax proprietary bayonet lens mount, and has a large body of accessories. The camera has several unique or uncommon features, and compared with contemporary professional camera bodies from rival manufacturers, like the Canon New F-1 or Nikon F3, the LX body is smaller and lighter, weighing in at 570 grams with its standard FA-1 finder.

The Pentax K-mount, sometimes referred to as the "PK-mount", is a bayonet lens mount standard for mounting interchangeable photographic lenses to 35 mm single-lens reflex (SLR) cameras. It was created by Pentax in 1975, and has since been used by all Pentax 35 mm and digital SLRs and also the MILC Pentax K-01. A number of other manufacturers have also produced many K-mount lenses and K-mount cameras.