He joined the League Two side from Sligo Rovers last year  on an initial 18-month deal and has started every league game this season.
The 27-year-old started his career at Galway and moved to Sheffield United in 2011, but did not make a first-team appearance for the Blades.
"I'm very pleased to get this sorted early" he told the club website.
Full-back Seamus Conneely has extended his contract with Accrington Stanley until 2018.