Why does Macbeth have Banquo killed?

Macbeth has Banquo killed because he sees him as a direct threat to his power and to the future of his crown.

The witches’ prophecy plants the fear: although Macbeth has become king, they predict that Banquo’s descendants—not Macbeth’s—will rule Scotland. That idea unsettles him deeply. He realizes that if the prophecy comes true, he will have committed murder “for nothing,” gaining the throne only to pass it to Banquo’s line. This turns Banquo from a trusted friend into a dangerous obstacle.

At the same time, Banquo himself is a problem. He is suspicious of Macbeth’s rise and represents a moral contrast—someone ambitious who refuses to act dishonorably. His very existence reminds Macbeth of the path he didn’t take. That combination of suspicion and integrity makes Banquo both a political and a psychological threat.

Macbeth’s decision also grows out of the violent logic he has already set in motion. After killing Duncan, he feels trapped. Violence has to be answered with more violence. He admits he is already so far “in blood / Stepp’d” that turning back would be as difficult as continuing. Killing Banquo becomes, in his mind, another necessary step to secure what he has stolen.

So, Banquo’s murder is calculated rather than impulsive. Macbeth hires murderers to kill both Banquo and his son Fleance, trying to erase the prophecy entirely. But Fleance escapes, which means the future Macbeth fears is still possible.

The killing marks a shift in Macbeth’s character. His murder of Duncan was driven by ambition and pressure, whereas his murder of Banquo is driven by paranoia and a desperate need to control fate. From this point on, Macbeth rules through fear, and every act of violence pulls him further into isolation and tyranny.