The Fifth Dimension, also known as The 5th Dimension, is an American popular music vocal group, whose repertoire also includes R&B, soul, and jazz.

The Fifth Dimension were best-known during the late 1960s and early 1970s for popularizing the hits "Up, Up and Away" and "Aquarius/Let the Sunshine In."

The five original members were Billy Davis, Jr., Florence LaRue, Marilyn McCoo, Lamonte McLemore, and Ron Townson. They have recorded for several different labels over their long career. Their first work appeared on the Soul City label, which was started by Imperial Records/United Artists Records recording artist Johnny Rivers. The group would later record for Bell/Arista Records ABC Records and Motown Records.

Some of the songwriters popularized by The Fifth Dimension later went on to careers of their own, especially Ashford & Simpson, who wrote "California Soul". The group is also notable for having more success with the songs of Laura Nyro than Nyro did herself, particularly in the cases of "Wedding Bell Blues", "Stoned Soul Picnic", and "Save the Country".

The Fifth Dimension is an American popular music vocal group, whose repertoire also includes R&B, Soul, and Jazz, best-known during the late 1960s and 1970s for popularizing hits of songwriters like Jimmy Webb, Laura Nyro, Burt Bacharach, Ashford & Simpson, and others, and helping to popularize “flower power” music with both white and black middle-class