Catherine Nelson (born Catherine Seeley, 26 November 1987) is a Sinn Féin politician from Northern Ireland. She was an MLA for Upper Bann from the 2016 election until 2017. Previously a schoolteacher at the non-denominational Belfast Boys' Model School, she resigned after allegedly enduring a campaign of harassment, which began after she was co-opted as a Sinn Féin councillor on Craigavon Borough Council in 2014. The Protestant Coalition opposed her employment at the school over her affiliation with Sinn Féin.