The book portrays a group of 'paisanos'—literally, countrymen—a small band of errant friends enjoying life and wine in the days after the end of World War I. Tortilla Flat was made into a film in 1942.

Steinbeck later returned to some of the panhandling locals of Monterey (though not the Mexican paisanos of the Flat) in his novel Cannery Row (1945).

Above the town of Monterey on the California coast lies the shabby district of Tortilla Flat, inhabited by a loose gang of jobless locals of Mexican-Indian-Spanish-Caucasian descent (who typically claim pure Spanish blood).

Most of the action is set in the time of Steinbeck's own late teenage and young adult years, shortly after World War I.

The following chapter titles from the work, along with short summaries, outline the adventures the dipsomaniacal group endure in order to procure red wine and friendship.

— After working as a mule-driver during The Great War, Danny returns to find he has inherited two houses from his deceased grandfather.

After escaping, Danny talks his friend, a clever man named Pilon, into sharing his brandy and his houses.

Pilon kills a rooster, rents Danny's second house for money which it is understood he will never pay, and exchanges paper roses for a gallon of Señora Torelli's wine.

5 How Saint Francis turned the tide and put a gentle punishment on Pilon and Pablo and Jesus Maria.

Pablo's candle, dedicated to St. Francis, burns down the house, while Danny, who is with Mrs. Morales next door, pays no attention.

The Pirate is the only paisano who works, and makes 25 cents a day selling kindling, but lives on food scraps given in charity, and saves the cash.

He and Pilon seek treasure in the woods on St. Andrew's Eve (29 Nov), and see the faint beam from a spot which they mark.

Next night, with wine Joe has gotten for a blanket he has stolen from Danny, they dig at the spot and uncover something labeled "United States Geodetic Survey + 1915 + Elevation 600 Feet".

— Danny trades stolen copper nails for money for a vacuum cleaner from Mr. Simon, to give to Sweets Ramirez (who has no electricity).

Sweets contentedly pretends she has electricity, pushing the machine over the floor while humming to herself, and Danny wins her favors.

He spends every evening with Sweets, until Pilon, telling himself he misses his friend, takes the vacuum and trades it to Torelli, the local shopkeep, for wine.

The friends take the thousand quarters which the pirate has earned over several years of woodcutting, to Father Ramon for him to buy a candlestick and feast.

However, the arrival of some stolen sacks of beans at the door is deemed a miracle, the children regain their health, and Teresina is also pregnant again.

14 Of the good life at Danny's house, of a gift pig, of the pain of Tall Bob, and of the thwarted love of the viejo Ravanno.

[1] Thomas Fensch, in an introduction to the novel, cited the idyllic setting, where "money is seldom needed" and all the characters desire is "enough food, a warm place to sleep, wine, and – occasionally – women and parties" as providing escapism for readers during the Great Depression.

The New York World-Telegram described the book as a "grand time" though the reviewer also felt that the ending "feels a little too casual to be moving".

[2] The New York Times, meanwhile, praised Steinbeck's "gift for drollery and for turning Spanish talk and phrases into a gently mocking English".