Portorož (pronounced [pɔɾtɔˈɾoːʃ] ⓘ; Italian: Portorose) is a Slovenian Adriatic seaside resort and spa settlement located in the Municipality of Piran in southwestern Slovenia.

In the early 20th century Portorož became one of the grandest seaside resorts in the Adriatic, along with Opatija, Lido and Grado, then as part of the Austrian Littoral.

[7] The history of the settlement is directly connected to that of the neighbouring town of Piran, with Illyrian settlers already living there in the prehistoric era.

A large development of the area followed only after the demise of the empire, with enlargement of the number of settlers seeking shelter from attacks by the Barbarians.

Due to increasing dissatisfaction with the feudal rule, as well as the rising power of the Venetian Republic, the settlement of Pirano signed a trade treaty with Venice, which included a lesser degree of autonomy.

One of the most important roles in the history of the settlement was the monastery of Saint Laurence, where the Benedictines healed rheumatic illnesses, ascites and other diseases with concentrated saltwater and saline mud.

A period of economic growth followed during the second Austrian rule, with enlargement of trade and locally important salt pans in nearby Lucija and Sečovlje.

In the aftermath of the Great War, the Treaty of Rapallo determined the Istrian peninsula to be from that point on a part of the Kingdom of Italy.

Under the royal and then fascist rule, the area found itself amidst economic decline and civil conflicts between the populace and the state.

In World War II, the area had not seen much action, although the important industrial hub of Trieste suffered multiple bombings.

In the second half of the 19th century, the leaders of the Pirano municipality and local doctors decided to stimulate tourism in the region, by offering health treatment by concentrated salt water and salina mud.

In the interwar period the settlement was slowly regaining its former glory when World War II severely crippled it again.

The industry faded away in the northern Adriatic region, until 1963, when Zavod za pospeševanje turizma, whose president was Anton Nino Spinelli, proposed a reopening of the casino.

Portorož belongs to the coastal municipality of Piran, located in the southwest of the Gulf of Trieste (at the northernmost point of the Adriatic Sea) between the boundaries of Italy to the north and Croatia to the south.

Since 2013 the Tilia Slovenia Open, a men's ATP Challenger tournament, takes place every summer on the same courts of the ŠRC Marina.

In 1958, the Portorož international chess tournament was won by Mikhail Tal; Bobby Fischer finished sixth, and was awarded the title of grandmaster at the (then) record age of 15.