The Owls exited the FA Youth Cup at the hands of Kiyan Coke-Miles-Smith, who fired a hat-trick to ease Reading through to round five.
Coke-Miles-Smith scored twice in the first half to put the Royals in the driving seat and crowned an eye-catching performance with a third after the break.
Both sides had equal amounts of possession in the early exchanges without troubling either keeper until the 27th minute when Coke-Miles-Smith took centre stage on a freezing night at Hillsborough.
The Royals’ wideman burst down the left side of the box, was expertly found by Luke Howard, and advanced to slide past Jack Phillips.
The visitors grew in confidence and doubled their advantage four minutes before half time.
Harris directed a sweeping ball towards the marauding Coke-Miles-Smith and from a similar position to his opener, casually flicked beyond Phillips with the outside of the boot.
Wednesday did respond positively and were a lick of paint away from halving the deficit straight from the restart when Jarvis Thornton fired against the crossbar from the edge of the area.
The cup-tie became more open in the second half as Wednesday chased the game. Devlin Moses scooped wide and then was inches away from connecting to a Bruno Fernandes feed across the face of goal.
The danger was leaving the back door open – which Reading exploited on the hour to put the tie out of reach.
Harris motored down the right and looked up to perfectly tee up Coke-Miles-Smith, who tapped home from six yards to complete his treble.
Still there was time for Reading to add a final coat of gloss as Harris took a neat ball from Jerae Jones into his stride on the angle inside the box and smashed high into the roof of the net.
Wednesday: Phillips, Rodrigues, Dawes, Kakay (Hunt 46), Swales, Emery, Bobea (Mbaya 54), Thornton, Moses, Fernandes, Johnson