Llansannor (Welsh: Llansanwyr) is a small hamlet in the Vale of Glamorgan, Wales, United Kingdom.

It contains a parish church, a pub (the City Inn, now closed), a primary school and a village hall, which has recently been rebuilt thanks to the efforts of the parishioners.

While agriculture remains important to the character of the area, many residents of the village are retirees or commute to work in nearby Cardiff.

The Valeways Millennium Heritage Trail passes through the parish, and the source of the River Thaw is nearby.

Famous residents include JPR Williams, former Welsh rugby fullback.