Ciarán Ó Lionáird (born 11 April 1988) is an Irish runner from Cork. He competed at the 2012 Summer Olympics in the 1500 metres. At the 2013 European Athletics Indoor Championships in March, he came 3rd in the Men's 3000 metres. Following the COVID-19 lockdown, he announced he was coming out of retirement, and his intention to compete in the Tokyo Olympics.