This was the first meeting between the sides since Christopher Schindler's match-winning penalty in the Championship play-off final at Wembley sent the Terriers into a two-season visit to the Premier League and left the Royals fighting successive campaigns against relegation.
But it was revenge in the sun for the Royals thanks to Ovie Ejaria's 71st-minute strike and Michael Morrison's 84th-minute header from a corner, which left Town seeking their first win of the campaign after the deflating experience of top-flight relegation.
Interim Huddersfield manager Mark Hudson handed a league debut to England Under-19 signing from Tottenham, defender Jaden Brown, and also left out the experienced Tommy Elphick. It meant Town reverted to a flat back four with Terence Kongolo moving inside to partner Schindler.
The other change to the starting line-up at Cardiff in midweek saw Adama Diakhaby replace Issac Mbenza out wide.
Jonathan Hogg and Trevor Chalobah provided insurance in front of them while pace out wide was designed to provide service for lone striker Karlan Grant, backed by Alex Pritchard. The ploy generally failed.
Reading, who included Argentinian forward Lucas Boye, who has joined on a season-long loan from Torino, countered with a 3-5-2 set-up but lost central defender Matt Miazga early on to a calf injury. It had little effect as Reading repelled everything Town threw at them aerially.
For all their pressure and possession - 72 per cent in the first half - Town went close just once in the opening half-hour, Schindler flashing a header wide from a corner - Grant rarely getting a touch of the ball.
The striker's first-time lay-off almost got Pritchard in and impressive driving force Chalobah drove a shot narrowly wide before the four minutes of stoppage time when Lucas Joao let fly from outside the area and Kamil Grabara beat the shot away - the only save of the half.
Grant was the first to go close after the break, bursting down the field only to see his fierce attempt beaten away by Rafael Cabral. Then Reading broke at pace, Andy Yiadom hitting the bar before Boye brought out the best from Grabara from inside the area.
That early burst of action promised better things to come and a curling shot from Pritchard was punched out for a Town corner.
However, the Royals struck in the 71st minute when Ejaria took a return pass from John Swift going down the left channel and stepped inside Schindler and fired home from the edge of the area.
Hudson used all three substitutes before Reading won a corner on the right and Morrison headed in at the far post from Swift's delivery.