Robert Jordan
The protagonist. An American fighting for the Republicans who is sent to blow a bridge behind enemy lines. Jordan is disciplined, thoughtful, and committed to the mission even as he falls in love and begins to doubt whether the cause can win. His final choice to stay behind and cover the retreat is the novel's moral climax.
Maria
A young Spanish woman rescued by the guerrillas after being assaulted and traumatized by Fascist soldiers. She and Jordan fall in love quickly. She gives Jordan something personal to fight for and represents both the human cost of the war and the possibility of life beyond it.
Pilar
Pablo's partner and the real leader of the guerrilla band. She is blunt, perceptive, and fiercely committed to the Republican cause. She pushes the mission forward when Pablo tries to sabotage it and serves as the moral backbone of the group.
Pablo
The nominal leader of the guerrilla band. He was once a feared and effective fighter, but fear and self-interest have made him unreliable. He steals Jordan's detonator caps, disappears, and eventually murders his own allies. He is Hemingway's portrait of what war does to a person over time.
El Sordo
A guerrilla leader in the same mountains who agrees to help Jordan. His band is tracked down and killed by Fascist cavalry before the operation. His death shows how isolated and vulnerable the Republican fighters are and raises the stakes for Jordan's mission.
Anselmo
An older guerrilla who serves as Jordan's guide and closest ally. He is deeply moral and hates killing, even though he does it. He dies during the bridge explosion. His death hits Jordan hard because Anselmo was one of the few people in the novel with uncomplicated goodness.
Golz
The Soviet general who gives Jordan his orders. He represents the larger military machine that treats individual fighters as expendable pieces in a strategic plan. Jordan's loyalty to Golz's orders drives the plot even when those orders seem pointless.