Jose Xavier put the hosts ahead from close range in the 56th minute and the win was sealed when the Magpies' Curtis Good turned Will Randall's 75th-minute cross into his own net.
Fulham currently occupy the final play-off spot but Wolves are now only five points behind them with two matches in hand.
Newcastle are seven points adrift of Wolves in 10th place.
Wolves: 9 Feb v Norwich (A) PL Cup
Newcastle: 12 Feb v Swansea (A) PL Cup