Louis Hector Leroux (27 December 1829, Verdun-11 November 1900, Angers) was a French painter in the academic style, affiliated by critics with the Néo-Grecs movement in art. He specialized in meticulously researched paintings of ancient Rome, especially depictions of women. He was best known for a series of some thirty paintings which spanned his entire career, depicting Vestal virgins. His daughter, Laura Leroux-Revault, was also a painter.

Born into a family of modest means in Verdun, Leroux was apprenticed to his father, a barber, before attending drawing classes at the Collège de Verdun, taught by a painter trained in the workshops of Antoine-Jean Gros and Michel Martin Drolling, who quickly spotted his talent. From 1849 to 1855, first the General Council of the Meuse and then the city of Verdun granted him annual scholarships to pursue his education in Paris.

In 1849, at the age of twenty, he entered the École des beaux-arts de Paris and for eleven years studied in the atelier of François-Édouard Picot, where he won medals for drawing, landscape, and historical composition. It was in Picot's studio that he met his lifelong friend Jean-Jacques Henner. He supported himself by working as a lithographer and as an illustrator for fashion journals.

In 1857, 1858, and 1859 he entered the annual competition for the Prix de Rome, administered by the Institut de France, which awarded the Grand Prix winner a multi-year scholarship to study and paint in Rome. He came close; his painting for 1857, when the assigned subject was the resurrection of Lazarus, received the Premier Second Grand Prix. After 1859, Leroux could no longer compete for the prize, which was restricted to entrants under the age of thirty. Determined that Leroux should go to Rome, his master Picot, along with Hippolyte Flandrin and Léon Halévy of the Institut, arranged for Leroux to receive a commission in 1860 from the École des beaux-arts de Paris to produce a copy of Titian's Sacred and Profane Love at the Galleria Borghese in Rome. The commission paid for his travel and provided lodging at the French Academy in Rome, alongside the winners of the Prix de Rome.

Leroux arrived in Rome on March 12, 1860. At the Villa Medici he was welcomed by his friend Henner, who had won the Prix de Rome in 1858, and subsequently met and befriended Henri-Michel-Antoine Chapu (Prix de Rome, 1855), Jules Joseph Lefebvre (Prix de Rome, 1861), Léon Bonnat, and Tony Robert-Fleury. In 1861, this group of friends, along with numerous other French artists, architects, musicians, and sculptors in Rome, formed a group called the Caldarrosti [fr] (Italian for grilled chestnuts), which met for annual banquets in Paris for many years afterwards.

After his copy of Titian was completed and sent to Paris, Leroux stayed on in Rome, supporting himself, alongside Henner, by painting picturesque scenes for the foreign tourists. He and Henner also traveled beyond Rome, including trips to Pompeii, immersing themselves in the landscapes, art, and archeology of Italy. "My path opened before me; I was fated for antiquity," Leroux later said. "There I was in Rome, surrounded by history, and it would have been hard for me not to follow my calling."

Leroux lived seventeen years in Rome, with excursions across Italy and beyond to Greece, Asia Minor, Turkey, and Egypt, as well as some return trips to France. In 1871 he married a young Italian, Giuditta Clelia Casali.

In 1863, at the age of 33, Leroux debuted at the Paris Salon with two paintings: Croyantes ("Believers," also known as Invocation to the Goddess Hygieia) and Une Nouvelle Vestale. Both were set in the ancient world, and both depicted women in religious contexts. Croyantes shows two women helping an ailing supplicant to approach a statue of a goddess in hopes of obtaining a divine cure, while Une Nouvelle Vestale depicts a candidate for the chaste life of a keeper of the holy flame of Vesta, protector of the city of Rome. In following years, Leroux would return repeatedly to both themes.