The victory was the first time Reading had won their opening game of the season since 2006.
Former Reading man Jay Tabb gave Ipswich a 16th-minute lead but a Cole Skuse own goal put Reading level a minute before half- time.
With 16 minutes to go Danny Guthrie scored the winner with a spectacular solo goal.
Guthrie was all on his own midway into the Ipswich half and beat Ipswich Scott Loach with a fierce effort which went over the keeper's head.
The opening goal had come from former Reading player Tabb, now an Ipswich player after spending the end of last season on loan with Mick McCarthy's side.
His 16th-minute shot was well saved by Alex McCarthy but as Reading scrambled to clear the ball it ran back to Tabb and he made no mistake with a low drive into the net.
Reading were posing few threats at this stage and their equaliser a minute before half-time was unexpected.
Garath McCleary sent in a deep cross from the left and Reading striker Adam Le Fondre jumped together with Skuse and Tyrone Mings.
The ball arrived in the middle of all three and it looked initially as if Le Fondre had headed the ball into the net but replays indicated that it was a Skuse own goal.
The goal came at a point when Reading fans were becoming restless at their side's attempt to threaten a solid Ipswich defence with a stream of high balls to Le Fondre.
The goal was a blow for an Ipswich side who must have been well pleased with their first half performance only to find themselves pegged back right on half-time.