Jementah is a mukim in Segamat District, Johor, Malaysia. It is the second largest town in the district with about 10,000 residents consisting mostly of Chinese communities. It is the third largest town in the district after Segamat Town and Labis. Strategically located 16 km from Segamat Town via Federal Route 23, Jementah is an important town in Segamat since it also houses the Johor Campus branch of Universiti Teknologi MARA.
There are two versions of stories of how Jementah got its name. The first version was during the foundation of a village which later became Jementah town center, some villagers complained, "Jemu, jemu, jemu! Asyik-asyik menebas lalang saja!" which literally meant that they felt bored for only cutting long grasses, and the others replied, "Entah, entah, entah!" (I don't know, I don't know, I don't know!). From the Malay words jemu and entah, local residents believed that the combination of those words formed the word Jementah.
Another version stated that the villagers were bored and tired of removing leeches which sucked their blood when they were working, and therefore the combination of the words jemu and lintah which means leech in Malay formed the word Jementah.
Jementah was once a site of the historic civil war in modern Johor history known as Jementah Civil War on 25 October 1879.
Coordinates: 2°26′N 102°41′E / 2.433°N 102.683°E