Rebecca Gratz (March 4, 1781 - August 27, 1869) was an American educator and philanthropist.

She was born in Philadelphia, Pennsylvania.

She was a promoter of religious, educational, and charitable institutions. Elected (1801) secretary of the Female Association for the Relief of Women and Children in Reduced Circumstances, Rebecca Gratz soon saw the need of an institution for orphans in Philadelphia, and she was among those instrumental in founding the Philadelphia Orphan Asylum in 1815. Four years later she was elected secretary of its board of managers, which office she continued to hold for forty years. Under her auspices were started a Hebrew Sunday-school (of which she subsequently became superintendent and president, resigning in 1864) and a Female Hebrew Benevolent Society (about Nov., 1819). In 1850 she advocated in "The Occident," over the signature "A Daughter of Israel," the foundation of a Jewish Foster Home, and her advocacy was largely instrumental in the establishment of such a home in 1855. Other organizations due to her efforts were the Fuel Society and the Sewing Society.

Rebecca Gratz is said to have been the model of Rebecca, the heroine of the novel Ivanhoe by Sir Walter Scott, whose attention had been drawn to her character by Washington Irving, with whom she was acquainted. The claim has been disputed, but it has also been well sustained in an article entitled "The Original of Rebecca in Ivanhoe," which appeared in "The Century Magazine," 1882, pp. 679-682.