The 20-year-old pop star got the tat Thursday in Los Angeles and controversy was stirred after the tattoo artist, Louis F. Perez III, posted a photo of his work on Instagram.
"Made sure my homey was strapped," he posted along with the photo, before later taking it down off his profile.
Some anti-gun activists said the tattoo could set a bad example for Malik's young fans.
"It is a shame that anyone would think it makes you look cool if you get a gun tattoo," said Ray Nelson, president of the Guitars Not Guns organization. "Promoting guns in fashion could lead to gun violence and we certainly don't need any more of that."