| Type: | commune |
| County: | Arad |
| Semlac | |
| Leader Name: | Letiția Stoian |
| Leader Party: | Independent |
| Leader Term: | 2020 - 2024 |
| Coordinates: | 46.1167°N 76°W |
| Elevation: | 90 |
| Area Total: | 83.11 |
| Population Total: | auto |
| Postal Code: | 317295 |
| Area Code: | +40 x57 |
Semlac (Hungarian: Szemlak) is a commune located in Arad County, in the western part of Romania, near the border with Hungary, is situated in the south-western part of the Arad Plateau, in the large valley of the Mureș River. Its territory occupies . It is composed of a single village, Semlac, situated from Arad.
According to the 2011 census, the commune has 3,667 inhabitants, out of which 78.4% were ethnic Romanians, 8.4% Roma, 2.67% Hungarians, and 2.32% Germans. At the 2021 census, Semlac had a population of 3,474; of those, 81.64% were Romanians, 6.48% Roma, 1.64% Germans, and 1.35% Hungarians.[1]
It is first mentioned in 1326. It was ravaged by the Turks in 1552, but later survived the occupation. In 1910, out of 5,676 inhabitants, there were 2,475 Romanians, 1,899 Germans, 601 Hungarians, 278 Slovaks, and 272 Ruthenians. Until the Treaty of Trianon, Arad County belonged to the district of Pecica. In 1992, out of 3,787 inhabitants, there were 2,947 Romanians, 286 Germans, 233 Gypsies, 181 Hungarians, and 140 others. To the south of the village, on the banks of the Mureș, lay the medieval village of Deușu, which has left no trace. The economy of the commune is mainly agrarian, the locality is well known in the region as an important grain-bearing vegetable-growing place. The livestock is based on pig and cattle raising.
Semlac contains a nature park.