The Royals went ahead through Lucas Joao’s header, only to be pegged back just before the hour mark by an Alfie Doughty curling effort.
The away side secured all three points with five minutes of normal time remaining through Will Vaulks.
Paul Ince’s side remain eight points clear of the relegation zone having played one more match than Barnsley.
Ince made one change from the 2-1 victory against Stoke in midweek with Tom Ince replacing Ovie Ejaria.
Meanwhile, the visitors made four changes following their 4-0 defeat against local rivals Swansea City last weekend.
The Royals came into the contest looking to extend their four game unbeaten run in the Championship which put them eight points clear of the relegation zone.
The home side edged the early stages and on the five minute mark, Joao setup Laurent with a clever backheel but the midfielder couldn’t get his shot past the Cardiff defenders.
The Royals then took the lead two minutes later when Tom Ince and Andy Yiadom combined down the right.
Yiadom then chipped a ball to the far post for Joao who rose above Perry Ng to head past Phillips for his seventh goal of the season.
Cardiff struggled to get any control in the game and could have gone further behind but Tom McIntyre couldn’t redirect John Swift’s free-kick on-target.
The away side had their first effort on goal after 20 minutes when Jordan Hugill flashed an effort from 25-yards over the bar after winning the ball in midfield.
Reading continued to work the ball well with Laurent and Joao linking up well before setting up Ince who smashed his effort over the bar.
Cardiff almost gifted the Royals a second through Swift nine minutes before the break when Ince intercepted a pass on the edge of the 18-yard box but he couldn’t get his shot away.
A minute after the interval, Yiadom wriggled free down the right but Joao couldn’t connect to his looping cross.
Steve Morison’s side had their first shot on-target after 49 minutes. Joe Ralls drilled a cross from the left but Colwill’s effort was straight at Orjan Nyland.
Cardiff continued to threaten and equalised just before the hour mark.
Ralls chipped pass found Doughty who latched onto the through ball and curled a shot past Nyland from inside the box.
The Royals manager decided to react to the leveller by switching Hoilett for Tom Dele-Bashiru.
Ince was forced into another substitution shortly after when John Swift went down and was replaced by Femi Azeez.
Reading struggled to regain control of the game after the equaliser and the away side took a deserved lead on 85 minutes.
Tommy Doyle’s pass parted the Royals defence leaving Will Vaulks to tuck home from six-yards.
With three minutes to go, Reading made their final change with Brandon Barker replacing Tom Ince.
Despite seven minutes of added time, the home side couldn’t create an opening to find an equaliser.
The Royals now look forward to an away trip to Bramall Lane to face Sheffield United on Good Friday, April 15, before returning to the Select Car Leasing Stadium on Monday, April 18 to play Swansea City.
Reading: Nyland, Yiadom, Morrison ©, Holmes, McIntyre, Drinkwater, Laurent, Swift, Hoilett, Ince, Joao.
Subs: Southwood, Thomas, Rahman, Barker, Dele-Bashiru, Ejaria, Azeez.
Cardiff City: Phillips, Drameh, Ng, Nelson, Bagan, Wintle, Ralls ©, Doyle, Colwill, Doughty, Hugill.
Subs: Luthra, McGuinness, Flint, Vaulks, Ikpeazu, Harris, Davies.
Goals: Lucas Joao 7’, Aidan Doughty 59’, Will Vaulks 85’.
