The Ems Ukaz, or Ems Ukase (Russian: Эмский указ, Emskiy ukaz; Ukrainian: Емський указ, Ems’kyy ukaz), was a secret decree (ukaz) of Tsar Alexander II of Russia issued in 1876, banning the use of the Ukrainian language in print, with the exception of reprinting of 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 Brotherhood of Sts Cyril and Methodius was broken up in Kiev, and its founder Nikolay Kostomarov and other prominent figures exiled or arrested, Ukrainian intellectuals were gaining further awareness of their cultural background. Hromada cultural associations were started in a number of cities, named after the traditional village assembly, and Sunday schools in the cities and towns (education had been neglected by the Russian Imperial administration). This was partly driven by publication 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 Cossack hetman Bohdan Khmelnytsky, Kulish's two-volume 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’.

EMS or Ems may refer to: