It was no more than West Ham deserved as they created the better chances against a Wolves side who have also moved into the mix for European qualification.
Declan Rice's curling effort against the post was the closest West Ham came to taking the lead before half time. But they eventually broke through when Soucek poked home from close range from a Michail Antonio cross.
West Ham climbed into fifth place with 45 points from 27 games, above Arsenal on goal difference and two behind fourth-placed Manchester United. However, sixth-placed Arsenal have three games in hand of the two sides immediately above them. Wolves are eighth with 40 points.
It was a scruffy goal that broke the deadlock but West Ham did not care. "We created a lot of opportunities, could have gone two or three up at one point. Wolves don't concede many goals," West Ham manager David Moyes said.