"Happy Birthday" is a 1981 single written, produced, and performed by Stevie Wonder for the Motown label. Wonder, a social activist, was one of the main figures in the campaign to have the birthday of Martin Luther King, Jr. become a national holiday, and created this single to make the cause known. Besides being released as a single, the song also appears on Wonder's album Hotter Than July.

The song, one of many of Wonder's songs to feature the use of a keyboard synthesizer, features Wonder lamenting the fact that anyone would oppose the idea of a Dr. King holiday, where "peace is celebrated throughout the world" and singing to King in the chorus, "Happy birthday to you". The holiday, he proposes, would facilitate the realization of Dr. King's dreams of integration and "love and unity for all of God's children".

Wonder used the song to popularize the campaign, and continued his fight for the holiday, holding the Rally for Peace Press Conference in 1981. United States President Ronald Reagan approved the creation of the holiday, signing it into existence on November 2, 1983. The first official Martin Luther King, Jr. Day, held the third Monday in January of each year, was held on January 20, 1986, and was commemorated with a large-scale concert, where Stevie Wonder was the headlining performer.

Although the single failed to reach the Billboard Hot 100, it charted on the R&B chart, and it became one of Wonder's biggest hits in the UK, reaching No.2 in the charts in August 1981.

Wonder also performed this song at the Diamond Jubilee Concert in London for the Diamond Jubilee of Elizabeth II.

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