The Ems Ukaz or Ems Ukase (Emskiy ukaz; Ems’kyy ukaz), was a secret decree (ukaz) of Emperor Alexander II of Russia issued on May 18, 1876, banning the use of the Ukrainian language in print except for reprinting old documents. The ukaz also forbade the import of Ukrainian publications and the staging of plays or lectures in Ukrainian. It was named after the city of Bad Ems, Germany, where it was promulgated.
In the 1860s, a decade and a half after the Imperial Russian government had broken up the Brotherhood of Sts Cyril and Methodius in Kiev (March 1847) and exiled or arrested its founder Mykola Kostomarov and other prominent figures, Ukrainian intellectuals gained further awareness of their cultural background. Hromada cultural associations, named after the traditional village assembly, started in a number of cities, and Sunday schools started in the cities and towns since the Russian Imperial administration had neglected education. The new cultural movement was partly driven by publications in both Russian and Ukrainian, including journals (such as Kostomarov's Osnova, 1861–62, and Hlibov's Chernyhosvs’kyy Lystok, 1861–63), historical and folkloristic monographs (Kostomarov's biography of the Cossack hetman Bohdan Khmelnytsky, Kulish's two-volume folklore collection Zapiski o Yuzhnoy Rusi, Notes on Southern Rus''', 1856–57), and elementary primers (Kulish's Hramatka, 1857, 1861, Shevchenko's Bukvar Yuzhnoruskiy, 1861). In Osnova, Kostomarov published his influential article "Dve russkiye narodnosti" ("Two Russian Nationalities").
Although Ukrainianism had been considered popular and somewhat chic in Russian cultural circles, a debate began at the time over its relation to the ideology of Russian Pan-Slavism, epitomised by a quotation of Pushkin ("will not all the Slavic streams merge into the Russian sea?"), and a rhetoric of criticism emerged. Conservative Russians called the Ukrainian movement a "Polish intrigue", and Polish commentators had been complaining that Ukrainianism had been used as a weapon against Polish culture in Right-Bank Ukraine.