Juliet's best friend from boarding school and the sister of Juliet's publisher, Sidney Stark. Sophie is the frequent recipient of letters from Juliet, but never writes a letter herself throughout the novel.
An eccentric Guernsey villager with a passion for classic romance novels by the Brontë sisters who becomes a close friend of Juliet's. Isola is constantly dabbling in strange hobbies: concocting potions and herbs to sell at the local market, studying phrenology, or keeping "spy notes" about the other islanders. Her quirks and mannerisms add a necessary dose of humor to life on Guernsey during the occupation.
An elderly fisherman and literary society member with a love for Shakespeare. Eben is the grandfather and caretaker of 12-year-old Eli, a young boy who had been sent to England for safety during the occupation. The knowledgeable Eben functions as both an invaluable resource about life on Guernsey during the occupation and a dependable friend who would do anything for his loved ones.
A 24-year-old French woman who lived in the same block as Elizabeth McKenna at Ravensbruck concentration camp. Remy was yet another recipient of Elizabeth's positive encouragement in terribly dark circumstances and the two women leaned on each other for support. Remy had especially taken comfort in Elizabeth's stories about Guernsey, believing it to be Heaven. Years later, Remy informs the islanders of Elizabeth's death and eventually comes to visit. The terrors she experienced at Ravensbruck have left Remy both physically and emotionally fragile.
An overly conservative middle-aged islander who detests both the Guernsey Literary and Potato Peel Pie Society and Elizabeth McKenna. She warns Juliet of the society's frivolous and detestable nature; however, like the other islanders, Juliet cannot take Adelaide's excessive and unwarranted accusations of immorality seriously.
Eben Ramsey's grandson who lost both of his parents during World War II. At the beginning of the German occupation, Eli is transported to England with the rest of the children for safety. Fortunately, a family on the British mainland cares for him and he safely returns to Guernsey five years later.
A former valet for a wealthy British man on Guernsey. When his master leaves the island during the German occupation, Booker mischievously overtakes the estate and lives a life of fake luxury. His wicked sense of humor remains unbending throughout the novel, even in his later story of being caught and spending several years in harsh concentration camps.
The German soldier that Elizabeth McKenna loved and the father of Kit McKenna. Although Christian is a commander for enemy troops, he is always kind to the islanders and loves Elizabeth and his daughter unconditionally. The islanders, particularly Dawsey, tell Juliet of his praiseworthy character.