The Hammers have enjoyed a fine first campaign under the Croatian.
The Croatian manager joined the club in the summer from Besiktas, signing an initial three-year deal.
It has been an impressive first season in charge so far though, with his side currently sixth in the table and within touching distance of the Champions League places.
That has far surpassed what was initially expected of him, with this season’s main remit having been to stay in the Premier League ahead of the move to the Olympic Stadium next season.
He has far surpassed that though, with it now looking likely that they will be playing European football in their first season at their new stadium next season, and much of that is down to the Croatian.
As a result, the Hammers are keen to reward him for this season's success with an improved deal at the club, which would see him stay until 2021 at least, reports the Mirror.
It's stated that Bilic has already met with co-owner David Sullivan last week, with his new contract thought to be on the agenda.
The news will come as excellent news to the West Ham faithful, who have taken quickly once again to their former defender upon his return to Upton Park.