Samuel Rosenthal (7 September 1837, Suwalki, then Russian Empire – 12 September 1902, Neuilly-sur-Seine, France) was a Polish-born French chess master.
Chess historian Edward Winter wrote, "He dedicated his life to chess-playing, touring, writing, teaching and analysing.
Despite only occasional participation in first-class events, he scored victories over all the leading masters of the time (Anderssen, Blackburne, Chigorin, Mackenzie, Mason, Paulsen, Steinitz and Zukertort).
In 1867, he took 9th in the Paris tournament (von Kolisch won), and lost a match to Gustav Neumann (+0-5=6) in Paris.
In 1869, he lost two matches to Neumann (+1-3=1) and (+2-4=1).
In July 1870, he tied for 8–9th in Baden-Baden.
The event was won by Adolf Anderssen.
Because of the Franco Prussian War of 1870–71, Rosenthal went to London.
In 1870/71, he won a match against John Wisker (+3-2=4).
In July–August 1873, Rosenthal took 4th, behind Wilhelm Steinitz, Joseph Henry Blackburne, and Anderssen, in Vienna.
In 1878, he tied for 7–8th in Paris (Johannes Zukertort and Szymon Winawer won).
In 1880, he won in Paris the first unofficial French Chess Championship (ahead of Albert Clerc and Jules Arnous de Rivière).
In 1880, he lost a match against Zukertort (+1-7=11) in London.