Agustin: Agustin is a faithful member of Pablo's band who is secretly in love with Maria.
Andres: Andres is a member of Pablo's guerilla band, Jordan sends him through Fascist lines to General Golz in an effort to call off the attack on the bridge.
Anselmo: Anselmo is a noble elderly Spanish peasant who acts as Jordan's guide through the mountainous Spanish terrain and who never waivers in the mission to blow up the bridge.
El Sordo: El Sordo is a deaf guerilla leader and his gang are supposed to provide back up support for Jordan when he blows up the bridge. However, he is killed in a Fascist cavalry attack and this puts the mission in jeopardy.
Fernando: Fernando is a faithful member of Pablo's guerillas and is given to spreading rumors. Fernando is the first man wounded in the mission to blow up the bridge.
Finito: Finito is the dead bull fighter and the former lover of Pilar who, although fearful outside of the bull ring turned into a lion in the ring. Pilar compares him unfavorably to Pablo.
General Golz: General Golz is a Russian general fighting on the side of the Republicans originally gave Jordan the order to blow up the bridge.
Robert Jordan: Robert Jordan is an American demolitions expert whom the guerillas call Ingles. He is fighting on the side of the Republicans against the fascists in the Spanish Civil War. The protagonist, all the action revolves around his last three days on earth in the company of his new love, Maria, as he prepares to dynamite a bridge held by the opposing Fascists.
Kashkin: Kashkin is Jordan's predecessor who died after blowing up a train. His death foreshadows Jordan's demise.
Krakov: Krakov is an influential Russian journalist who befriended Jordan at a luxury Madrid hotel. Krakov attempts to help Jordan at the end of the novel but finds it is too late.
Maria: Maria, a cropped-hair nineteen-year-old girl, was a prisoner raped by the Fascists before she was rescued by the guerillas. She is an orphan. Pilar loves her like a daughter and protects her from men but guides her towards Jordan with whom she falls instantly in love.
Pablo: Pablo is the leader of the guerillas. He was formerly a powerful leader but has recently become a coward and reluctant to fight for the cause. His authority has been usurped by his woman, Pilar, and he feels resentful toward the more youthful and masculine Jordan who in turn considers Pablo a threat to the mission.
Pilar: Pilar, referred to as Pablo's woman, is a strong no-nonsense woman who has taken control of the band of guerillas. Highly superstitious, she reads Jordan's palm early on but refuses to tell him she sees death in his hand.
Rafael: Rafael is a gypsy who provides comic relief, Rafael is a member of Pablo's band.