Miss Marilla Cuthbert and Mr. Matthew Cuthbert, elderly siblings who live together at Green Gables in Avonlea, on Prince Edward Island, decide to adopt an orphan boy from the asylum as a helper on their farm. Through a series of mishaps, what ends up under their roof is a precocious girl of eleven named Anne Shirley. Anne is bright and quick, eager to please but dissatisfied with her pale countenance dotted with freckles, and with her long braids of red hair. Being a child of imagination, however, Anne takes much joy in life, and adapts quickly, thriving in the environment of Prince Edward Island.
The rest of the book recounts her continued education at school, where she excels in studies very quickly, her budding literary ambitions and her friendships with people such as Diana Barry, Jane Andrews and Ruby Gillis and her rivalry with Gilbert Blythe, who teased her about her red hair and for that acquired her hatred, although he apologised many times. They compete in class and Anne one day realises she no longer hates Gilbert, but won't admit it. The book also follows her misadventures in quiet, old-fashioned Avonlea. These adventures include her games with her friendship group ( Diana, Jane and Ruby) and her domestic mistakes such as dying her hair green. Anne, along with Gilbert and Jane, eventually goes to the Queen's Academy and obtains a teaching license in one year, in addition to winning the Avery Prize in English, which allows her to pursue a B.A. at Redmond College. The book ends with Matthew's death, caused by a heart attack after learning of the loss of all his and Marilla's money. Anne shows her devotion to Marilla and Green Gables by giving up the Avery Prize, deciding to stay at home and help Marilla, whose eyesight is diminishing, and teaching at White Sands school, the nearest school availible. To show his friendship, Gilbert Blythe gives up his teaching position in the Avonlea School to work at White Sands School instead, thus enabling Anne to teach at the Avonlea School and stay at Green Gables all through the week. After this kind act, Anne wholly forgives Gilbert and they become good friends.