The Nigeria international, 23, played 24 times for the Royals last term but missed a significant chunk of the season due to injury.
He becomes the sixth signing of the summer for Rovers, who are still operating under a transfer embargo due to their breach of Financial Fair Play regulations.
Speaking about the ex-Everton trainee, Reading boss Steve Clarke told his club’s official website: “Last season was a frustrating one for Hope Akpan due to injury and lack of game-time.
“It is an area of the pitch where we are well covered and it would be wrong to deny Hope the chance to play matches and start to move his career forward again.
“He was always a good person in my squad with the correct attitude towards training and I wish him well for the future.”