The hosts dominated from the very beginning of the match and put in a strong first half performance which was only missing the opening goal.
That eventually came in the early stages of the second half when Lopez was quickest to a poor back pass to put Wolves ahead and send Molineux into raptures.
Wolves controlled the rest of the afternoon and saw out a historic and crucial win ahead of the international break - giving Wolves their first victory at home over the Baggies since May 2011.
Analysis
Raul Jimenez had already been ruled out of the game due to a knee injury, but Wolves were dealt a further blow as Ladislav Krejci was unavailable due to a calf problem.
Kieran Trippier was deemed fit enough to start, however.
The two teams walked out to an incredible atmosphere at Molineux and it was the home side that made a solid start.
A superb cross-field ball from Nasser Djiga had Mateus Mane running down the left and his cross reached Rodrigo Gomes, but it was an awkward height and his effort was easily caught by goalkeeper Max O’Leary.
Marshall Munetsi then had an opening after a good move and had his shot blocked.
Wolves were playing confidently on the ball and some impressive technical play resulted in a corner, in which they should have scored.
The ball fell to Djiga from close range and his header was set to nestle in the back of the net, until O’Leary pulled off a tremendous save to tip the ball onto the crossbar.
Wolves appeared up for the occasion and were dominating the ball, while creating plenty of problems down the right flank as Lopez and R.Gomes combined.
Wolves came close again as Mane twisted and turned down the left before getting a cross in for Munetsi at the near post, but his header was turned around the woodwork by O’Leary.
Lopez then had a good chance when the ball fell for him inside the box, but he fired wide.
Wolves were unable to break the deadlock before the break, but entered half-time very much in control of the game.
That opening goal came just five minutes into the second half as Lopez pounced on a dreadful back pass from Albion defender Nathaniel Phillips to easily finish beyond O’Leary.
Molineux erupted as Wolves took the lead and the atmosphere intensified as the players flew into tackles and asserted more dominance over their rivals.
They came close to a second when Adam Armstrong fed Mane and then received the ball back, before seeing his shot from inside the box deflect wide for a corner.
Albion nearly scored against the run of play when a free-kick from Isaac Price, which was clearly meant to be a cross, almost went all the way in and it required Jose Sa to tip it wide.
Wolves remained in control of the game, but began to sit deeper defensively as the clocked ticked down towards six minutes of added time.
There was a nervousness around the stadium as Wolves cleared their lines amid waves of Albion attacks.
But the Baggies never truly tested Sa and Wolves saw out the remaining minutes to record a historic victory.
Key Moments
GOAL 50 Lopez pounces on a mistake to put Wolves ahead
Teams
Wolves: Sa, Trippier, Djiga, Toti, Bueno, Andre, Munetsi (James, 78), R.Gomes (B.Traore, 88), Lopez (Doyle, 73), Mane (Bellegarde, 73), Armstrong (Neave, 88).
Subs not used: Virginia, Konan, Tchatchoua, Traore.
West Brom: O’Leary, Styles, Campbell, Phillips, Townsend, Whitwell (Nzingoula, 61), Molumby (Collyer, 84), Diakite, Price (Tunde, 84), Morgan, Heggebo (Stewart, 61).
Subs not used: Ingram, Mepham, Pereira, Bany, Horn Myhre.