Bill MacLeod, commissioning editor BBC Alba, said the channel was delighted to recommission the show.
He said: “An t-Eilean will once again transport viewers to one of the most dramatic landscapes in the world with a taut and twisty story that will keep them on the edge of their seats until the final few frames.”
Arabella Page Croft, executive producer at Black Camel Pictures, said it was “simply fantastic” to be working on a second series.
She added: “We can’t wait to get going with this brand-new gripping Hebridean mystery and thrilling tale with DS Kat Crichton at the helm.”
An t-Eilean series two is funded by MG Alba, BBC, Screen Scotland, Black Camel Pictures and Highlands and Islands Enterprise.
Western Isles local authority Comhairle nan Eilean Siar will provide support around the locations.