The 34-year-old has decided to hang up his boots after failing to sign for a new club following his departure from Bury at the end of last season.
"I don't think too many people will be surprised," BBC Sport quotes Healy as saying. "I have been without a club for five months. It's dawned on me that it's time for a new challenge. The career is over and it's time to move on.
"I didn't enjoy my last six months at Bury because of a number of circumstances. I still thought in the summer that I was capable and would be fit enough if I got a good pre-season under my belt.
"But that didn't happen and it's hard going down to the gym and doing 20 or 30 minutes of aerobic stuff on your own. It would have been great to have achieved 100 caps but at the same time I didn't want to be getting token caps."
Healy netted 36 goals in 95 appearances for Northern Ireland.