Charles Bregler (May 1864–September 24, 1958) was an American portrait painter and sculptor, and a student (and disciple) of artist Thomas Eakins. Bregler wrote about Eakins's teaching methods, and amassed a large collection of his minor works, memorabilia and papers. Following Bregler's death, his widow safeguarded the Eakins collection for decades before selling it to the Pennsylvania Academy of the Fine Arts.
Bregler was an orphan, whose father died when he was 3 and whose mother died when he was 12. He apprenticed as an artisan, learning to decorate fancy leather goods. As a teenager, he won a scholarship to the Franklin Institute's evening drawing classes. His first wife was Elizabeth Yohn (1871–1944), and his second wife (and widow) was Mary Picozzi (1917–1987).
Bregler enrolled at the Pennsylvania Academy of the Fine Arts in 1883. Eakins, who had trained at the École des Beaux-Arts, was director of the art school and its instructor in painting and drawing. In early January 1886, Eakins had a male model remove his loincloth during an anatomy lecture before either an all-female or a mixed male-and-female class. Using a fully nude male model was contrary to PAFA policy, and Eakins received a January 11 letter of reprimand. The "loincloth incident" ignited a firestorm of sordid accusations against Eakins, and he was forced to resign.
All 55 of the school's male students and 18 of the 30 female students signed petitions threatening to withdraw from PAFA unless Eakins was reinstated. PAFA's board declined to do so. Bregler was one of 16 students (all men) who left to form the Art Students' League of Philadelphia, with Eakins as their unpaid teacher. The League's tuition was initially set at $25, but was raised to $40 for the 8-month 1886-87 season, and finally $50. The school never had more than forty-one students, and sometimes had as few as twelve. Bregler was enrolled for all 7 years of the League's existence.
Bregler returned to PAFA in 1894 after the League's demise, and exhibited in PAFA's annual exhibitions: 1892, 1896, 1898 and 1903. He exhibited a portrait at the 1893 World's Columbian Exposition in Chicago, and one at the 1904 Louisiana Purchase Exposition in St. Louis. He was one of four former Eakins students who held a joint exhibition of paintings in Philadelphia in 1924.