Sylvan Ebanks-Blake's 33rd-minute penalty and Bjorn Sigurdarson's 82nd-minute strike - his first Wolves goal - gave Wanderers three league wins in a row for the first time since April 2009.
It left Posh rooted to the bottom of the table having lost all seven of their matches so far this season.
Peterborough boss Darren Ferguson dropped George Boyd. The transfer-listed Boyd started on the bench and was replaced in midfield by teenager Joe Newell. Otherwise it was the same team that was beaten 2-1 by Bristol City in midweek.
Youth star Jaanai Gordon-Hutton was included among the Posh substitutes.
Striker Ebanks-Blake and midfielders Tongo Doumbia and Slawomir Peszko were recalled to the Wolves starting line-up as manager Stale Solbakken rotated his squad once again.
Solbakken also handed a first start of the season to Kevin Foley who replaced Richard Stearman in defence.
Peterborough began positively. Lee Tomlin might have done better with an early effort and Grant McCann stung Carl Ikeme's palms with a long-range shot after eight minutes.
Wolves were restricted to long-range attempts with Karl Henry, Doumbia and Ebanks-Blake not causing Posh goalkeeper Robert Olejnik too much concern.
It was a sloppy piece of play from the hosts that led to the opening goal.
Posh gave the ball away in midfield and the resulting Wolves attack ended up with McCann fouling Ebanks-Blake, who picked himself up to blast home from the penalty spot.
Kevin Doyle twice threatened to extend Wolves' lead before half-time but was narrowly off target on each occasion.
Bakary Sako also had a couple attempts at goal at the start of the second half before Ebanks-Blake was denied by Olejnik in the 53rd minute.
Sigurdarson shot narrowly wide midway through the second half before Bako went close again in the 77th minute.
Substitute Boyd tried his luck from long range in a rare Peterborough attack.
But Wolves sewed up the points with eight minutes remaining when Sigurdarson got on the end of Doyle's pass and coolly lifted the ball over Olejnik.