Umag (Croatian pronunciation: [ûmaɡ]; Italian: Umago) is a coastal city in Istria, Croatia. The city hosts the yearly Croatia Open ATP tennis tournament on clay courts.

It is the westernmost city of Croatia, and the municipality includes Savudrija which is westernmost point of Croatia.

Umag has a population of 7,769 (2001), total municipal population 12,901 (2001). Like many other towns in Istria, Umag has a multi-ethnic population. Croats comprise an absolute majority with 59.6%; Italians 18.3%, Serbs 3.8%, Slovenes 2.2%, Bosniaks 1.7%, Albanians 1.3% and those regionally declared (as Istrians) make up the final 1.57%.

Umag was mentioned for the first time in the 7th century by an anonymous citizen from Ravenna, but had already existed in Roman times. Proof of that is found in the numerous remains of Roman retreats, the so-called villa rustica uncovered all along the coast. The town's history is closely linked to the settlement of Sipar whose ruins can be found on the narrow cape, six kilometres north of Umag. In the 9th century the fortified settlement of Sipar was devastated by invaders, the Neretva pirates. However, after this unfortunate incident Umag grew in significance thanks also to its location, a small islet separated from the mainland with a narrow channel. It was actually this location to safeguard the settlement from the continuous invasions throughout the centuries. The Roman period of relative prosperity was substituted by one of insecurity caused primarily by frequent invasions, outbreaks of plague, cholera, and malaria. The number of its dwellers declined rapidly. Umag became part of the reigns of Odoacre, Theodoric and was ruled by the Longobards too.