Events from the year 1878 in art.

• November 25 – 26 – James McNeill Whistler's libel case against English art critic John Ruskin over a scathing 1877 review of Whistler's painting Nocturne in Black and Gold – The Falling Rocket is heard in the High Court of Justice in London. Whistler wins a farthing in nominal damages and only half of the costs, leading to his bankruptcy, and alienates patrons.
• French critic Théodore Duret publishes the pamphlet Les Peintres impressionistes.
• Czech painter Karel Klíč perfects the photogravure process.

• Ivan Aivazovsky – Sea View by Moonlight
• Jules Bastien-Lepage
  • Les Enfants Pecheurs ("The child fishers")
  • Les Foins ("Haymaking")
• Reinhold Begas – Mercury and Psyche (marble, Berlin, Germany)
• Emmanuel Benner – Lakeside Dwelling
• Gustave Caillebotte
  • Bather about to dive
  • The Canoes (Museum of Fine Arts of Rennes)
  • Fisherman on the bank of the Yerres
  • The Orange Trees
  • Rue Halévy: view from the sixth floor
  • View of rooftops, effect of snow
• Mary Cassatt
  • In the Loge
  • Portrait of the Artist
• Eduard Charlemont – The Moorish Chief
• William Merritt Chase
  • A Fishmarket in Venice
  • The Mandolin Player
• Stanisław Chlebowski – Sultan Bayezid prisoned by Timur
• James Collinson – The Holy Family
• Evelyn De Morgan – Night and Sleep
• Maurycy Gottlieb – Jews Praying in the Synagogue on Yom Kippur
• Jean-Jacques Henner
  • The Magdalene
  • Portrait of M. Hayem
• Ivan Kramskoi – Portrait of the Artist Alexander Litovchenko
• Robert Walker Macbeth – Sedge Cutting in Wicken Fen, Cambridgeshire, early morning
• Édouard Manet
  • At the Café
  • Blonde Woman with Bare Breasts (Musée d'Orsay, Paris)
  • The Plum
  • The Rue Mosnier with Flags
• Jan Matejko – Battle of Grunwald
• John Everett Millais
  • A Jersey Lily
  • The Two Princes Edward and Richard in the Tower, 1483
• Pierre-Auguste Renoir – Madame Georges Charpentier and her children
• Ilya Repin – Self-portrait
• Briton Rivière – Persepolis
• Auguste Rodin – The Walking Man (bronze)
• Félicien Rops – Pornocrates
• Dante Gabriel Rossetti
  • The Blessed Damozel (probable completion date)
  • A Vision of Fiammetta
• August Friedrich Schenck - Anguish
• Alfred Sisley – Snow at Louveciennes (Musée d'Orsay, Paris)
• James Tissot
  • Kathleen Newton In An Armchair
  • Seaside
• Viktor Vasnetsov – The Knight at the Crossroads
• Hubert von Herkomer – Eventide: A Scene in the Westminster Union
• William Frederick Yeames – And When Did You Last See Your Father? (Walker Art Gallery, Liverpool)

• 4 January – Augustus John, Welsh painter (died 1961)
• 16 January – Karl Isakson, Swedish painter (died 1922)
• 14 February – Bohumil Kafka, Bohemian Czech sculptor (died 1942)
• 27 February – Max Silberberg, German Jewish industrialist and art collector (killed after 1942)
• 12 March – Gerda Höglund, Swedish religious painter (died 1973)
• 27 March – Kathleen Bruce (later Lady Scott), English sculptor (died 1947)
• 28 March – Abraham Walkowitz, American Modernist painter (died 1965)
• 1 April – Alfred Flechtheim, German art dealer, collector and publisher (died 1937)
• 2 April – Émilie Charmy, French artist (died 1974)
• 24 April – Jean Crotti, French painter (died 1958)
• 26 May – Spencer Gore, English painter (died 1914)
• 9 August – Eileen Gray, Irish furniture designer and architect (died 1976)
• 7 October – Feliu Elias, Spanish caricaturist and painter (died 1948)
• 8 October – Alfred Munnings, English equine painter (died 1959)
• 14 November – Julie Manet, French painter and art collector (died 1966)
• 23 November – Frank Pick, English transport administrator and patron of art and design (died 1941)
• 24 November – Norman Wilkinson, English marine artist (died 1971)
• 27 November – William Orpen, Irish portrait painter (died 1931)

• January 26 – Théophile Schuler, French painter and illustrator (born 1821)
• February – Tito Angelini, Italian sculptor (born 1806)
• February 9 – Nicolas Gosse, French historical painter (born 1787)
• February 19
  • George Paul Chalmers, Scottish painter (born 1833; died as the result of a street attack)
  • Charles-François Daubigny, French painter (born 1817)
• February 26 – Alexandre Antigna, French painter (born 1817)
• March 3 – Joseph Bonomi the Younger, English sculptor, artist, Egyptologist and museum curator (born 1796)
• April 14 – Ludovic Piette, French impressionist painter (born 1826)
• April 23 – Jaroslav Čermák, Czech historical painter (born 1831)
• May 25 – Antoine Laurent Dantan, French academic sculptor (born 1798)
• June 10 – Tranquillo Cremona, Italian painter (born 1837)
• June 16 – Kikuchi Yōsai, Japanese painter most famous for his monochrome portraits of historical figures (born 1788)
• August 21 – Conrad Martens, English-born landscape painter (born 1801)
• October 5 – Francis Grant, Scottish painter (born 1803)
• November 11 – Robert Havell, Jr., English principal engraver of Audubon's The Birds of America (born 1793)
• November 16 – Đura Jakšić, Serbian painter and poet (born 1832)
• December 19 – Joseph Nash, English watercolour painter and lithographer (born 1809)
• date unknown – Amédée Faure, French portrait painter (born 1801)