三味线是日本的一种弦乐器。乐器由四角状的扁平木质板面上蒙上皮制成，琴弦从头部一直延伸到尾部。通常会用银杏形的拨来弹奏。

一般认为起源于中国的三弦，大约成形于15世纪左右。中国的传统乐器三弦经过琉球王国（现在的冲绳），产生了早期琉球群岛的“三线”，之后传到日本本土，逐渐成形。而早期的琉球三线后来又受本土三味线的影响被改良成现在的冲绳三线。

The shamisen or samisen(三味線, literally "three strings"), also called sangen(三絃, literally "three strings"), is a three-stringed, Japanese musical instrument derived from the Chinese instrument sanxian. It is played with a plectrum called a bachi.

The Japanese pronunciation is usually "shamisen" but sometimes "jamisen" when used as a suffix (e.g., Tsugaru-jamisen). (In western Japan, and often in Edo-period sources, it is sometimes "samisen.")