The show, starring Douglas Henshall as detective Jimmy Perez and based on the novels of Ann Cleeves, has been confirmed for six new episodes.
Filming will take place in Shetland and around Scotland next year with casting set to be announced in due course.
The most recent six-part series, made by ITV Studios for the BBC, attracted a 29.5% audience share in Scotland equating to 690,000 viewers for its first four episodes.
The average viewing figures among UK audiences was just under six million.
Alongside leading man Henshall and cast regulars Alison O'Donnell and Steven Robertson, it featured a host of guest stars including Brian Cox, Alex Norton, Julie Graham, David Hayman and Bill Paterson.
Christopher Aird, BBC Head of Drama Production Scotland, said: "Shetland is a really distinctive crime series that has proved hugely popular with audiences both here in Scotland and across the rest of the UK.
"We have some really exciting plans for viewers from DI Perez and his team."
Elaine Collins, executive producer for ITV Studios, said: "I'm delighted Shetland has been recommissioned. It's been a pleasure to work with actors like Douglas Henshall, Alison O'Donnell and Steven Robertson, who have made Jimmy Perez and his team a regular fixture in the homes of millions."