"I've really enjoyed my time with Wales," Johnson said.
"It's been a real honour to play for them but I now feel it is the right time to retire from the international scene and concentrate on my club football."
Johnson Quits International Scene
The 30-year-old played 15 times for Wales over the past 6 years has joined Mark Pembridge, Andy Melville and Gary Speed in deciding to quit the international arena and concentrate only on domestic football.