Pauline Marie Pfeiffer (July 22, 1895 – October 1, 1951) was an American journalist, and the second wife of the writer Ernest Hemingway.
Pfeiffer was born in Parkersburg, Iowa, on July 22, 1895, moving to St. Louis in 1901, where she went to school at Visitation Academy of St. Louis. Although her family later moved to Piggott, Arkansas, Pfeiffer stayed in Missouri to study at University of Missouri School of Journalism, graduating in 1918. After working at newspapers in Cleveland and New York, Pfeiffer switched to magazines, working for Vanity Fair and Vogue. A move to Paris for Vogue led to her meeting Hemingway and his first wife, Hadley Richardson in 1926.
In the spring of 1926, Hadley became aware of Hemingway's affair with Pauline, and in July, Pauline joined the couple for their annual trip to Pamplona. On their return to Paris, Hadley and Hemingway decided to separate, and in November, Hadley formally requested a divorce. They were divorced in January 1927.
Hemingway married Pauline in May 1927, and they went to Le Grau-du-Roi to honeymoon. Pauline's family was wealthy and Catholic; before the marriage Hemingway converted to Catholicism. By the end of the year Pauline, who was pregnant, wanted to move back to America. John Dos Passos recommended Key West, and they left Paris in March 1928.
They had two sons, Patrick and Gregory. Hemingway drew upon Pfeiffer's difficult labor with one son as the basis for his character Catherine's death in A Farewell to Arms. Pfeiffer's devout Roman Catholic beliefs led to her support of the Nationalists during the Spanish Civil War, while Hemingway backed the Republicans.