A term that refers to a broad set of popular music styles, genres and scenes, that may include psychedelic rock, psychedelic folk, psychedelic pop, psychedelic soul, psychedelic ambient, psychedelic trance, psychedelic techno and others. Psychedelic rock is also commonly called acid rock.

During the mid to late 1960s, music of the psychedelic genre, in the basic sense of the word, was incorporated by almost every band/recording artist at that time, which makes psychedelia a very broad style. However, psychedelia as a strict genre of music is difficult to identify/label because of the many contrasting musical groups that interpreted then demonstrated this concept as their own form of music.

It is easy to classify certain music as being psychedelic by its use of elaborate studio effects, exotic instrumentation or surreal lyrics, but this does not necessarily means that it is truly psychedelic music. Even the heavier and more aggressive bands of the late 1960s (such as MC5 and Iron Butterfly), used some typical psychedelic techniques, but psychedelia was also strongly associated with the lighter or sometimes more mainstream acts of the era (the Beatles, Strawberry Alarm Clock, Pink Floyd, Sopwith Camel).

It is important to note that few of the works described as psychedelic were successful in capturing the various effects associated with the psychedelic experience. Some such as Sgt Pepper's Lonely Hearts Club Band used various tricks of the recording medium to try to evoke the psychedelic 'trip', such as the hallucinogenic effects of time dilation (by slowing down or speeding up the recording tape), curious echoes (by tape delays of various kinds) and other assorted perceptual variations and new techniques such as panning and phasing.