巴拉莱卡琴（Балалайка），又称三角琴，俄罗斯吉他，是俄罗斯的一种弦乐器。

巴拉莱卡琴的琴腹呈三角形，颈细长有品，背板平坦；有圆形音孔，有3根弦，品（фрет）可移动。由演奏者背挎着，用手指拨奏，或用皮革制的拨子进行弹奏。其音色与吉他有相似之处。

现代的巴拉莱卡琴分为大小六种，最大的琴身高度相当于普通人的身高。由于尺寸和大小不同，音域和音高不一，倘若十几架一起演奏，可以抵上一个交响乐队，因此它可以克服其他单品种弹拨乐器音域不足、音质较单调的缺陷，从而在配器时充分展示自己的特色。

巴拉莱卡是俄罗斯民间歌舞中常用的伴奏乐器，在20世纪也用于大型巴拉莱卡乐队。

The balalaika (Russian:балала́йка, pronounced [bəɫɐˈɫajkə]) is a Russian stringed musical instrument with a characteristic triangular body and three strings.

The balalaika family of instruments includes instruments of various sizes, from the highest-pitched to the lowest: the piccolo balalaika, prima balalaika, secunda balalaika, alto balalaika, bass balalaika, and contrabass balalaika. The prima balalaika is the most common; the piccolo is rare. There have also been descant and tenor balalaikas, but these are considered obsolete. All have three-sided bodies; spruce, evergreen, or fir tops; and backs made of three to nine wooden sections (usually maple). They are typically strung with three strings, and the necks are fretted.