Conrad Henri Roy III (September 12, 1995 – July 12, 2014) was an American marine salvage captain who died by suicide at the age of 18. His girlfriend, 17-year-old Michelle Carter, had encouraged him in text messages to kill himself.

The case was the subject of an investigation and involuntary manslaughter trial in Massachusetts, colloquially known as the "texting suicide case." It involved scores of text messages, emails, and phone calls recorded between Carter and Roy in the lead up to his death, in which Carter repeatedly texted Roy to kill himself. Roy had seen numerous mental health professionals and had been prescribed psychiatric medication.

After a bench trial, presiding judge Lawrence Moniz found Carter guilty of involuntary manslaughter, concluding that she wanted Roy dead and that her words coerced him to kill himself. Moniz's decision rested chiefly on Carter's final phone call in which she ordered a terrified Roy to go back inside his truck as it filled with carbon monoxide. Initially sentenced to 2½ years in prison, Carter had her penalty later reduced to 15 months, of which she served 11 months and 12 days. The case raised questions pertaining to the nature and limits of criminal responsibility.