The yueqin (Chinese: 月琴; pinyin: Yuèqín; Japanese: 月琴, romanized: Gekkin; Korean: 월금/月琴, romanized: Wolgeum; Vietnamese: Nguyệt cầm/月琴 or Vietnamese: Đàn nguyệt/彈月), also called a moon lute or moon guitar, is a traditional Chinese string instrument.

The word yueqin is made of two characters, yuè (月 "moon") and qín (琴 "stringed instrument, zither").

The yueqin originated from the ruan, a similar stringed instrument that may have been invented as early as the 2nd century BC, during the Western Han dynasty.

The yueqin typically has a round soundboard with no sound-hole, but inside the sound box are one or more strands of wire attached only at one end, so that they vibrate, giving the instrument a particular timbre and resonance.

This allows for a greater control over timbre and intonation than their western counterparts, but makes chordal playing more difficult.

While both instruments have a moon-shaped soundboard, the modern ruan uses a bridge, whereas the yueqin simply attaches the strings the frame, similar to the design of the pipa.

Northern yueqin have a very short neck, and have bamboo in both the front and back, requiring the performer to hold the instrument away from their body.

A common technique in performance is "snapping" the pick on the string (similar to Japanese shamisen.)