The viola (in French, alto; in German Bratsche) is a string instrument played with a bow which serves as the middle voice of the violin family, between the upper lines played by the violin and the lower lines played by the cello and double bass.

The casual observer may mistake the viola for the violin because of their similarity in size, closeness in pitch range (a mere perfect fifth separates the two), and identical playing position (both rest on the left shoulder). However, the viola's timbre sets it apart: its rich sonority is more full-bodied than the violin's, dark-toned and earthy. The viola's mellow voice is frequently used for playing inner harmonies, and it does not enjoy the wide solo repertoire or fame of the violin.

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The viola has 4 strings: C,G,D,and A. C is the lowest (an octave below middle C on the piano) and A is the highest (just above middle C). In essence, it is tuned a 5th lower than the violin and an octave higher than the cello.

The viola is played in the same manner as the violin: the instrument is placed on the left shoulder, the left hand is used to press the strings onto the fingerboard, and the bow is held in the right hand and drawn across the strings. The viola can also be plucked which is when no bow is used. Instead, the index finger of the right hand pulls the string back to produce a short, choppy sound. You learn pizzicato (plucking, pronunced pits-a-cah-toe) before bowing.

Violas come in a range of sizes, the smallest usually being 12 inches, the largest: 17 inches. A "full size" instrument is anywhere from a 15 inch to 17 inch (I happen to play a 16 inch). The difference between buying a violin and a viola is that there isn't a specific full size. The violin has a standard full size (13-14 inches). The average adult violist plays between a 15 inch and a 16 1/2 inch. 17 inch instruments are hard to play because they're so large. If you're a parent, ask your child's teacher or orchestra director about what size to get. However, nothing beats going to a violin shop and playing the instrument yourself with the advice of a well-educated sales person. I should know. Buying an instrument without playing it first is probably the worst thing you can do, and it's a waste of money if the instrument isn't right for you.