JEROME Thomas' brilliant brace saw Albion come from behind to end their three-game winless run.
Roberto Di Matteo's men took an age to get going and fell behind to Matthew Mills' header in the seventh minute.
But Thomas had a point to prove on his return from a three-game ban and he levelled with a fine solo effort on the half-hour mark.
The Baggies then put Reading under fierce pressure and they finally buckled when Thomas deservedly fired the hosts ahead in the 65th minute with his third goal in two league games.
Youssouf Mulumbu made the points safe with a stunning goal three minutes from time - his third of the campaign.
Di Matteo's side deserve great credit for turning a poor start into an such an accomplished display against stubborn opposition.
With leaders Newcastle facing an evening kick-off at Nottingham Forest, Albion started the game knowing they could go back to the top if they won by three clear goals.
Di Matteo made two changes from the goalless draw at Preston a fortnight ago, with the injured Chris Brunt and benched Abdoulaye Meite making way for back-from suspension Thomas and Luke Moore.
Gonazalo Jara started his first game at centre-half alongside Jonas Olsson.
Brendan Rodgers made three changes to his Royals side, with Khalifa Cisse, Mills and Noel Hunt coming in for Darren O'Dea, Brynjar Gunnarsson and Simon Church.
Albion started sluggishly and suffered a setback in the sixth minute when Roman Bednar was stretchered off after falling awkwardly. He was replaced by Chris Wood.
It went from bad to worse a minute later when Reading got their noses in front.
Brian Howard swung a free-kick to the back stick where centre-half Mills ghosted in front of his marker to head past the stranded Scott Carson.
The goal momentarily stirred the Baggies into life and Adam Federici just beat Wood to Moore's goalbound header after the Royals failed to clear a Graham Dorrans flag-kick.
But it was Reading who should have scored next.
Jobi McAnuff had his head in his hands after volleying over from only eight yards from former Baggies loan signing Shaun Cummings' pinpoint centre.
Albion had strong penalty appeals turned away in the 14th minute when Moore was scythed down by Ivar Ingimarsson - but referee Anthony Taylor adjudged the offence to have occurred just outside the box.
Marek Cech arced the resulting free-kick into the Reading wall.
Joe Mattock finally unlocked the visitors' defence on 24 with a delicious ball down the line. Wood advanced into the box before firing well wide from a tight angle.
Albion then caught Reading on the break with a swift counter-attack.
Dorrans found Thomas with a stunning 50-yard pass and the former Charlton winger skipped inside Cummings before seeing his 15-yard drive finger-tipped wide by Federici. Inexplicably, the officials awarded Reading a goal-kick!
However, Thomas wasn't to be denied on the half-hour mark when he fired Albion level.
Moore cleared a Howard corner and McAnuff put his team in trouble with a dangerously under-hit back-pass.
Thomas nicked the ball past the on-rushing Federici, who had raced well outside his area, before out-pacing Cummings to stab into the empty net.
Albion had now got well on top and Moore fizzed a terrific turn and shot just past the right-hand post from Gianni Zuiverloon's ball into the box.
Thomas caused Reading even more problems just before half-time when he controlled Cech's angled pass and saw his centre narrowly evade the unmarked Zuiverloon at the far post.
Albion were soon back on the attack after the break and it took a wonderful near-post save from Federici to deny Wood's acrobatic volley from Mattock's centre.
Reading were struggling to get out of their own half and Albion wasted a glorious chance on 59.
Moore did well to control Mattock's centre before seeing his near-post shot blocked by Federici.
The rebound flew straight to the unmarked Cech 12 yards out who wastefully fired over the gaping net.
Moments later, Federici had to be alert again to clutch Zuiverloon's near-post shot.
Reading did not threaten again until the 62nd minute when Jimmy Kebe saw a deflected 20-yard drive fly a yard wide of the right-hand post.
Back came Albion and they wasted another golden chance a minute later.
Dorrans spearheaded a terrific counter-attack before finding Thomas, who instantly laid the ball into the path of Cech. The ex-Porto ace was unmarked in the heart of the penalty area but saw his effort saved at point-blank range by Federici.
But the Baggies finally got the goal their forceful play deserved in the 65th minute.
Wood put Thomas clear of the Reading defence were a terrific through-pass and the ex-Arsenal ace calmly strode into the penalty area before slipping the ball under Federici.
The Reading keeper was pushing Thomas all the way for the man-of-the-match vote and he pulled off another stunning save to keep out Cech's cheeky chip from Zuiverloon's lay-off.
Albion were rarely troubled again and Mulumbu put the icing on the cake on 87.
Federici vacated his goal to punch clear Dorrans' centre under pressure from Jonas Olsson and Mulumbu expertly volleyed the ball over the retreating Reading keeper and just under the bar from 20 yards.
There was still time for Dorrans to come agonisingly close to scoring THE goal of the season in any division.
The Scotland international was positioned just inside the Reading half when he spotted Federici off his line and launched an audacious chip.
But the Royals keeper managed to leap backwards and tip the ball over his bar at full stretch, thus denying Dorrans a David Beckham-esque goal.
The Berkshire boys rallied in stoppage time but Howard and Kebe both failed to test Carson, who enjoyed a quiet afternoon between the sticks.
ALBION (4-4-2): Carson; Zuiverloon, Jara, Olsson, Mattock; Cech (Teixeira 80), Mulumbu, Dorrans, Thomas; Moore (Meite 80), Bednar (Wood 6). Subs not used: Kiely (gk), Cox, Martis, Koren.
READING (4-2-3-1): Federici; Cummings, Ingimarsson, Mills (Rasiak 72), Bertrand (O'Dea 43); Karacan, Cisse; Kebe, Howard, McAnuff; Hunt (Long 53). Subs not used: Hamer (gk), Tabb, Robson-Kanu, Sigurdsson.
GOALS: ALBION - Thomas (30, 65), Mulumbu (87). READING - Mills (7).
BOOKINGS: ALBION - Zuiverloon (foul 62). READING - O'Dea (foul 86).
REFEREE: A Taylor (Cheshire).
ALBION STARMAN: Jerome Thomas.