"Happy Birthday Sweet Sixteen" is a pop song released in 1961 by Neil Sedaka.

Both of these songs exhibiting similarity to "Happy Birthday Sweet Sixteen" were penned by the team of Carole King and Gerry Goffin (King and Sedaka were close friends in high school, and Sedaka was known for his appropriation of other popular song motifs in his work).

The narrator sings the song to a younger acquaintance who had up to that point had more of a sibling-like relationship (“when you were only six, I was your big brother”) upon her sixteenth birthday, reminiscing about the ups and downs of their friendship thus far and declaring that now that she has grown from an awkward tomboy (comparing her younger self to the subject of the Rodgers and Hart song "My Funny Valentine").

[3] Other musicians on the record include Al Casamenti, Art Reyerson and Charles Macey on guitar, Ernie Hayes on piano, George Duviver on bass, Artie Kaplan on sax, Seymour Barab and Morris Stonzek on cellos, David Guillet, Joseph Haber, Louie Haber, Harold Kohon, David Sackson, Maurice Stine, Louis Stone, and Arnold Goldberg on violins, and Phil Kraus and George Devens on percussion.

"It Hurts to Be Sixteen," with a melody written by Sedaka, was a minor hit for Andrea Carroll (herself 16 at the time she recorded it) in 1963.