Head First
Head First or Headfirst may refer to:

Music
Head First (The Babys album) (1979)
Head First (Badfinger album) (recorded 1974, released 2000)
Head First (Goldfrapp album) (2010), or its title track
Head First (Uriah Heep album) (1983)
"Head First", a song by Aerosmith from the Get a Grip sessions

Other Media
Head First (book series), a series of books on computer programming by Kathy Sierra and Bert Bates
HeadFirst PD, a library of public-domain software
Headfirst Productions, a defunct UK video game studio
Head First (TV series), Australian 2010s TV documentary series
"Head First", an episode of the sitcom The King of Queens
Headfirst (La Tête la première), a 2012 Belgian film starring Alice de Lencquesaing

Linguistics
Head-first, a property whereby a word comes before the words that modify it