Cillian Gallagher (born 23 July 1997) is a professional rugby union player from Ireland. He primarily plays as a lock, but can also play in the back row. Gallagher currently plays for Irish provincial side Connacht in the Pro14, having come through the team's academy. A student of Summerhill College in Sligo, Gallagher first played rugby for Sligo RFC in Strandhill. He played for the club through under-age level before joining Galway Corinthians.