Robert Jordan An American college instructor of Spanish, fighting as a demolition expert with the Loyalists in the Spanish Civil War.
Pablo Leader of the guerilla band whose aid Jordan enlists in the destruction of a bridge.
Pilar Pablo's mujer, who has kept the band together in spite of the fact that Pablo has "gone bad."
Maria A young girl whom the guerillas have rescued from enemy captivity and who falls in love with Jordan.
Anselmo An old man, one of the few members of Pablo's band whom Jordan trusts.
General Golz A Russian officer, one of the many military "observers" sent to aid the Spanish communists in the war, who is directing the forthcoming attack.
Kashkin Another Russian, Jordan's predecessor as demolition man with Pablo's band. He is dead when the book opens.
El Sordo The leader of another guerilla band which is hiding out in the vicinity of Pablo's cave.
Joaquin A young boy, member of El Sordo's band.
Eladio, Agustin, Andres, Primitivo, Fernando, and Rafael Members of Pablo's band.