Omurtag Municipality (Bulgarian: Община Омуртаг) is a municipality (obshtina) in Targovishte Province, Northeastern Bulgaria, located in the so-called Fore-Balkan area north of the Stara planina mountain.

The municipality embraces a territory of 401.7 km2 (155.1 sq mi) with a total population of 21,356 inhabitants, as of February 2011.

Omurtag Municipality includes the following 43 places (towns are shown in bold): The following table shows the change of the population during the last four decades.

According to the 2011 census, among those who answered the optional question on ethnic identification, the ethnic composition of the municipality was the following: [8] The municipality of Omurtag had relatively favourable demographic indicators compared to the Bulgarian average.

The continued childbirth decline came amid the falling number of women of childbearing age because of emigration to Western Europe (especially Germany and the Netherlands).