Romanel-sur-Lausanne (ʁɔmanɛl syʁ lɔzan, literally Romanel on Lausanne; Romanél) is a municipality in the canton of Vaud in Switzerland, located in the district of Lausanne.
Romanel-sur-Lausanne is first mentioned in 1184 as Romanes.
Romanel-sur-Lausanne has an area, , of (depending on calculation method). Of this area, or 59.7% is used for agricultural purposes, while or 3.8% is forested. Of the rest of the land, or 37.8% is settled (buildings or roads).
Of the built up area, industrial buildings made up 5.2% of the total area while housing and buildings made up 14.2% and transportation infrastructure made up 12.5%. Power and water infrastructure as well as other special developed areas made up 3.1% of the area while parks, green belts and sports fields made up 2.8%. Out of the forested land, 1.7% of the total land area is heavily forested and 2.1% is covered with orchards or small clusters of trees. Of the agricultural land, 55.6% is used for growing crops and 1.4% is pastures, while 2.8% is used for orchards or vine crops.
The municipality was part of the olf Lausanne District until it was dissolved on 31 August 2006, and Romanel-sur-Lausanne became part of the new district of Lausanne.
The municipality is part of the agglomeration of Lausanne. Until the 1960s, it consisted of a linear village on the Lausanne-Echallens road, which then grew to become part of the greater Lausanne area.
The blazon of the municipal coat of arms is Gules, a Fountain Gules and Argent fimbriated Argent, Chief of the same.
Romanel-sur-Lausanne has a population () of . , 19.4% of the population are resident foreign nationals. Over the last 10 years (1999–2009 ) the population has changed at a rate of 5.9%. It has changed at a rate of -1.3% due to migration and at a rate of 7.8% due to births and deaths.
Most of the population () speaks French (2,737 or 89.2%), with German being second most common (128 or 4.2%) and Italian being third (66 or 2.2%). There is 1 person who speaks Romansh.
Of the population in the municipality 605 or about 19.