The ex-Australia boss, one of the most decorated in the sport who won the 2013 World Cup with the Kangaroos, has signed a two-year deal subject to receiving UK clearance.
Sheens, who turns 69 later this month, was sacked as Robins coach in June with the East Yorkshire club fearing a relegation fight.
Championship club Widnes have been on the look-out for a new head coach since Kieron Purtill’s decision to quit last week in order to take up an assistant coach role at Hull FC.
A Widnes statement read: “The club have been working hard over the last week to find the perfect candidate to take the club forward, and given the transitional phase from a full-time to a part-time operation it was imperative to find the right person to begin the rebuilding process.
“It was a thorough and extensive search. However, a coach of Tim’s calibre stands out head and shoulders above the rest and it is an incredible coup for the club, which speaks volumes of the attractiveness of this role.
“As a club, we believe this appointment gives us the ability to change the course of our future, and although we are still operating under a part-time budget that has been considerably reduced from previous seasons, this appointment is a huge step forward for Widnes Vikings.”
As well as well as four Grand Final wins in Australia - three with Canberra Raiders and another with Wests Tigers - Sheens has also coach New South Wales’ State of Origin and worked as director of rugby at Salford Red Devils.
He has experience of the Championship having joined relegated KR at the end of 2016 and helped them achieve an immediate promotion back into Super League.