Arrowsmith is a novel by American author Sinclair Lewis, first published in 1925. It won the 1926 Pulitzer Prize (which Lewis declined). Lewis was greatly assisted in its preparation by science writer Paul de Kruif, who received 25% of the royalties on sales, although Lewis was listed as the sole author.

Arrowsmith is an early major novel dealing with the culture of science. It was written in the period after the reforms of medical education flowing from the Flexner Report on Medical Education in the United States and Canada: A Report to the Carnegie Foundation for the Advancement of Teaching, 1910, which had called on medical schools in the United States to adhere to mainstream science in their teaching and research.

The book was adapted by Hollywood as Arrowsmith in 1931, featuring Ronald Colman and Helen Hayes. It was nominated for four Academy Awards, including Best Adapted Screenplay.