Zimmerman was facing a second-degree murder charge with a sentence of up to life in prison. He was also acquitted on the lesser charge of manslaughter.
Martin, 17, was fatally shot after a violent encounter with Zimmerman in Sanford, FL on Feb. 26, 2013.
Throughout the trial the prosecution argued that Zimmerman pursued Martin, assuming the teen was a criminal, while the defense said that Zimmerman killed Martin in self-defense.
The case caused a national debate on racial profiling and civil rights.