Tony Romo Says He Has Alcohol Dependency, Pleads No Contest to OWI

Tony Romo's taking accountability for his actions ... pleading no contest to the OWI charge he was hit with in Wisconsin -- and admitting on social media that he has an alcohol problem.

The former Dallas Cowboys superstar shared a vulnerable post on Instagram Tuesday ... in which he said he has faced a "personal failure" by pleading no contest to a civil OWI offense in Wisconsin.

Romo notes multiple back surgeries ending his playing career early ... and these left him with chronic pain.

He says he developed a dependency on pain medication first ... and, while attempting to get off the pain meds, he says he ultimately just replaced it with a dependency on alcohol.

Romo writes, "As I have told my three young sons: when you fall short, you stand up and take full responsibility. That is an important first step. The harder and more important step is examining the path that brought you here and making the changes necessary to move forward."

He says he's working with a team of doctors to address his issues ... adding he's also grateful for the support of his family, friends and the NFL community at large.

Some of Romo's famous friends -- including Tom Brady -- dropped heartfelt messages of support in the comments section of his post.