墨西哥街头乐队 (西班牙语：Mariachi) 是一种墨西哥式的乐队，通常由至少3个小提琴手、2个小号手、1个墨西哥吉他手、1个vihuela琴手与1个guitarrón琴手组成；乐队成员通常身着华丽的墨西哥服饰「Charro」，头戴宽边的墨西哥帽。乐队通常在婚礼、节庆等正式场合上表演。

Mariachi指的是「墨西哥街头乐队」或有人称「流浪乐手」是一种墨西哥式的乐队，。有关Mariachi的起源是众说纷纭，有理论认为，Mariachi是来自法语「婚礼」-mariage一词，因为在婚礼中常出现各类型的音乐，但问题是在1864年法国人到达墨西哥之前Mariachi就已经存在。但也有人认为Mariachi这个名字来自一种歌颂圣母玛丽亚（mah-ree-ah AH-chay）的节庆与音乐表演。但一般相信Mariachi应该是19世纪起源于墨西哥南部的哈利斯科州（Estado Jalisco）。

Mariachi (/mɑːriˈɑːtʃi/; Spanish: [maˈɾjatʃi]) is a musical expression that dates back to at least 19th century Western Mexico. It is a tradition that can be defined by eight socio-musical elements: mariachi instrumentation and texture, musical genres and subgenres, performance methods and styles, singing styles and forms, dance styles, performative space, performance clothing, and the word "mariachi". Each element has its own history, originated at varying moments in time and in different regions of the Western Mexican countryside, and some, not all, had to have converged in order for the mariachi tradition to be what it has become.