蓝调（英文：Blues，解作「蓝色」，又音译为布鲁斯）是一种基于五声音阶的声乐和乐器音乐，它的另一个特点是其特殊的和声。蓝调起源于过去美国南方黑人奴隶的赞美歌、劳动歌曲。蓝调中使用的“蓝调音”、“调用与回应“的演唱方式源自西非的文化。蓝调对后来现代流行音乐有非常大的影响，散拍、爵士乐、蓝草、节奏蓝调、摇滚乐、乡村音乐、放客音乐和所有从前述音乐衍生出来的其他流行歌曲，甚至现代的古典音乐中都有引用自蓝调的元素。在诗歌里这个词常被用来描写忧郁情绪。

蓝调一词是与“蓝色魔鬼”（Blue devils）一致的意思，意思是情绪低调、忧伤、忧郁。早在1798年乔治·科曼就写过一部名为《蓝色魔鬼，一幕滑稽戏》（one-act farce Blue Devils）的滑稽戏。19世纪这个词被用来表示震颤谵妄和警察。在美国黑人音乐中这个词的应用可能更老。1912年威廉·克里斯托弗·汉迪的《孟菲斯蓝调》是这个词在音乐中最早的书面纪录。

Blues is a genre and musical form that originated in African-American communities in the "Deep South" of the United States around the end of the 19th century. The genre developed from roots in African-American work songs combined with European American folk music. Blues incorporated spirituals, work songs, field hollers, shouts, and chants, and rhymed simple narrative ballads. The blues form, ubiquitous in jazz, rhythm and blues and rock and roll, is characterized by the call-and-response pattern, the blues scale and specific chord progressions, of which the twelve-bar blues is the most common. The blue notes (or "worried notes") which are often thirds or fifths which are flatter in pitch than in other music styles, are also an important part of the sound. Blues shuffles or walking bass reinforce the trance-like rhythm and form a repetitive effect called a groove.