The Municipality of Šempeter–Vrtojba (Slovene: Občina Šempeter - Vrtojba, Italian: Comune di San Pietro-Vertoiba) is a municipality in Slovenia. The municipality comprises the town of Šempeter pri Gorici and the adjacent village of Vrtojba.
Both settlements used to be suburbs of town of Gorizia until 1947, when they become part of Yugoslavia while Gorizia remained a part of Italy. They have had a separate urban development since then. Nowadays, the Municipality of Šempeter–Vrtojba forms a single continuous urban area with the neighbouring towns of Nova Gorica and Gorizia. Since May 2011, these three municipalities have been joined in a common trans-border metropolitan zone, administered by a joint administration board.
Vrtojba (Italian: Vertoiba) is a settlement in the Municipality of Šempeter–Vrtojba in the Slovene Littoral region of Slovenia. A border crossing into Italy is located here. On the Italian side of the border, opposite Vrtojba, is the suburb of San Andrea (Slovene: Štandrež), now part of the town of Gorizia (Slovene: Gorica).
Vrtojba was first mentioned in the early 13th century as Toyfa, Toyua, or Tojva in a list of properties belonging to the Counts of Gorizia. Its etymology is unknown, but is likely of pre-Slavic origin. By 1350 it was listed as Vertoib. The population increased in the 16th and 17th centuries with settlers from areas further south affected by Ottoman raids moving to the fertile countryside around Gorizia. In the late 18th and early 19th centuries, Vrtojba became known for its early season vegetables and potatoes with regular supply to the markets of Gorizia and beyond. Although this fame still continues to some extent today, industrialization of Nova Gorica after the Second World War meant workers also settled in the village and the urban expansion in recent decades has virtually turned Vrtojba into the southern suburbs of Nova Gorica.