Napoléon on the Battlefield of Eylau (French: Napoléon sur le champ de bataille d'Eylau) is an oil painting of 1808 by French Romantic painter Antoine-Jean Gros. Completed during the winter of 1807–1808, the work has become an icon of the emerging style of French Romanticism. It depicts a moment from the aftermath of the bloody Battle of Eylau (7-8 February 1807) in which Napoléon Bonaparte surveys the battlefield where his Grande Armée secured a costly victory against the Russians. Although Napoleon on the Battlefield of Eylau retains elements of history painting, it is by far Gros's most realistic work depicting Napoleon and breaks from the subtlety of Neoclassicism. The painting's influence can be seen in the works of artists like Théodore Géricault and Eugène Delacroix.
In early February 1807, the Russian army, under the command of Levin August von Bennigsen, was in full retreat while being pursued by Napoléon Bonaparte's Grande Armée. The field armies of Russia's ally, the Kingdom of Prussia, had been decisively defeated by the Grande Armée at the double Battle of Jena–Auerstedt on 14 October 1806. This left the Russian army as the only major land force opposing Napoléon in the War of the Fourth Coalition. After some failed attempts to disrupt the French advance, Bennigsen decided to regroup his retreating forces at the Prussian village of Eylau (now Bagrationovsk, Kaliningrad Oblast).