A tenor violin (or tenor viola) is an instrument with a range between those of the cello and the viola. An earlier development of the evolution of the violin family of instruments, the instrument is not standard in the modern symphony orchestra. Its tuning, typically G2–D3–A3–E4 – an octave below the traditional violin, places the range between the cello and viola and thus is sometimes confused with the modern baritone violin which has the same tuning on the standard violin body. As a formal development, the 17th-century tenor violin existed as an instrument with a body larger than a viola but with a short neck. In earlier designs, the tenor was played upright in the musician's lap. Tenor violin parts were written in tenor clef.
Improvements in string technology in the 18th century led to greater focus of sound coming from the viola and cello ranges leading to a diminished role for tenor violins and violin makers constructed fewer of these instruments. It is known that Antonio Stradivari constructed two different models of tenor violin as well as tenor variations of violas.
Tenor violins regained popularity in Germany during the late 19th century to the early 20th century. They were meant to be played on the lap, but some were also fitted with chin rests for playing on the shoulder. The body is 18 inches (460 mm) long and 30 inches (760 mm) long overall and the ribs being 1⁄8 inch (3.2 mm) higher than today's standard 16-inch (410 mm) viola. As with the violins of the period, many of these examples feature fretted fingerboards.
By analogy with the vocal quartet of soprano-alto-tenor-bass, a few composers featured the tenor violin as the voice between the alto of the viola and bass of the cello (e.g. Felix Draeseke or Sergei Taneyev. In contemporary musical improvisation these instruments are again finding a place.
Modern incarnations of the tenor violin are the viola profunda and the violotta (both held at the shoulder). In the modern new violin family or violin octet, the tenor violin exists as an instrument tuned an octave below the violin and approximately the same size as a 1⁄2 cello. The baritone violin in the same is an enlarged version of the cello.