Authors born in 1978
- Ian Somerhalder Actor, 1978
- Inga Cadranel Actress, 1978
- Jack Thorne Screenwriter, 1978
- Jaclyn Victor Singer, 1978
- Jaime Herrera Beutler Politician, 1978
- Jaime Ray Newman Actress, 1978
- Jake Johnson Actor, 1978
- Jake Pavelka Aviator, 1978
- Jake Shears Singer-Songwriter, 1978
- James Badge Dale Actor, 1978
- James Corden Actor, 1978
- James Edward Olliges Jr. Singer-Songwriter, 1978
- James Franco Actor, 1978
- James Jackson Toth Singer-Songwriter, 1978
- Jamie Carragher Football Player, 1978
- Jamie Clayton Actress, 1978
- Jane Chen Activist, 1978
- January Jones Actress, 1978
- Jason "Gong" Jones Musician, 1978
- Jason Biggs Actor, 1978
- Jason Boyd Musician, 1978
- Jason Powers Rapper, 1978
- Jay Hernandez Actor, 1978
- Jeff Nichols Film Director, 1978
- Jen Psaki Politician, 1978
- Jenny Frost Singer, 1978
- Jensen Ackles Actor, 1978
- Jeremy Camp Musician, 1978
- Jesse Ball Novelist, 1978
- Jesse Kellerman Novelist, 1978
- Jesse Metcalfe Actor, 1978
- Jesse Watters Political Commentator, 1978
- Jessica Cutler Blogger, 1978
- Jessica Valenti Writer, 1978
- Jillionaire Disc Jockey, 1978
- JJ Feild Actor, 1978
- Joanna Gaines Designer, 1978
- Joanne Kelly Actress, 1978
- Jodi Lyn O'Keefe Actress, 1978
- John Legend Singer, 1978