Llanrumney High School (Welsh: Ysgol Uwchradd Llanrhymni) was an English medium co-educational, community secondary school located in the Llanrumney area of Cardiff, Wales.
The school served the communities of Llanrumney, Pentwyn and St Mellons on the eastern side of Cardiff and was opened in the 1957 alongside Rumney High School. It was a mixed-sex school with 647 children aged 11–16 attending during the Estyn school inspection in 2006, showing a reduction compared to 774 in 2000. 4% came from ethnic minority backgrounds.
A proposal to close Llanrumney High School and Rumney High School was published by Cardiff Council on 20 March 2009. A total of 1257 objections were registered during the objection period to 20 May 2009. The proposal was due to be implemented by September 2012.
Reasons cited include that both of the schools are old and falling into a state of disrepair. The intention was to build a new high school on the Rumney Recreation Ground with some of the playing fields at the existing Llanrumney High School site being retained whilst the rest of the site along with Rumney High School would be sold off. The proposed new school would form a partnership with Cardiff High School and Willows High School, with pupils entering further education at Coleg Glan Hafren, or elsewhere in the city where appropriate. Nonetheless, the school remained open, in part due to the cancellation of the "Rumney Rec" proposals.
The school eventually closed at the end of the 2013 summer term, with all students being transferred to Rumney High School, which was renamed Eastern High School in September 2013.