Following a strong start to the season under the former Liverpool assistant boss, the Baggies are currently placed in eighth in the Premier League table.
"The gaffer is absolutely great," Foster told the club's official website. "He doesn't really fluctuate. He's so calm all the time and just gets on with it and that's the only way you can be as a head coach.
"He's not a ranter or a raver and the lads really appreciate that. I don't think anybody responds to being shouted at and berated. He just maintains that same persona and the lads appreciate it because we know what we're going to get from him."
West Brom take on Sunderland next weekend.