Reading totally dominated the first half and should have scored more than the two goals they did.
City had a better second half without ever really threatening to fight their way back into the game.
Reading took the lead after 12 minutes. Full-back Ryan Bertrand brought the ball out of defence and sent it forward to Jobi McAnuff, who was back in the side after suspension.
McAnuff sent in a superb cross from the right wing and Gylfi Sigurdsson was able to head firmly past City keeper Dean Gerken from close range.
Sigurdsson then added a second in the 21st minute after being bundled over by City's Paul Hartley.
Referee Paul Taylor pointed to the penalty spot and Sigurdsson himself stepped up to score.
He almost added a third seven minutes before the interval but his shot was headed off the City goalline by Paul Hartley.
It was Sigurdsson in action yet again with a Reading chance three minutes before the break.
His close-range effort was blocked by Gerken and the rebound struck Sigurdsson in the face before going behind for a goal kick.
City looked a little brighter early in the second half, although all the best they could manage early on was a Bradley Orr shot that went well wide of the Reading goal.
Then came City's most dangerous move with Jamal Campbell-Ryce winning a battle with Brynjar Gunnarsson before drawing an excellent close-range save from Reading's Australian keeper Adam Federici.
As Reading got back into the game, Shane Long blazed over the City bar when it seemed easier to score and then Jimmy Kebe ended a long solo run with a shot that Gerken managed to block.
In the first half, Lee Johnson, son of City manager Gary, was booked for a blatant trip on Reading's Brian Howard as he bore down on goal.
City's Bradley Orr and Louis Carey, plus Reading's Gunnarsson and Matt Mills were also shown yellow cards.