Smiley Face Killer

Smiley face killer may refer to:


 * Keith Hunter Jesperson (born 1955), serial killer who used the smiley face symbol on his letters to the police and prosecutors
 * Robert Lee Yates (born 1952), serial killer who used plastic bags with a smiley face printed on them to cover the heads of his victims
 * Smiley face murder theory, a theory about smiley faces near the bodies of young men killed by drowning between 1992 and 2018
 * Smiley Face Killers (film), a 2020 American slasher film