Ismail al Ajmi and Ali al Busaidy found the target in the 33rd and 87th minutes, respectively.
A crowd of 2,000 turned up for the contest as an enterprising Oman kept its opponent under pressure right from the outset.
Shortly after the halfhour mark, Ajmi befuddled Reading keeper Stuart Taylor from the edge of the box.
He squeezed the ball in from the right with Taylor expecting it the other way. Oman shut the door on Reading in the closing minutes when an opportunistic Busaidy smashed in a rebound off the post following a shot from captain Hussain Mudhaffar's shot.
The Red Warriors, coached by Paul Le Guen, now head to Selhurst Park to take on Jimmy Kebe’s new club Crystal Palace next Tuesday.
The friendlies and training sessions in the UK are part of Oman's preparations for the upcoming Asian Cup Group A qualifier against Jordan on October 15.