The family says someone stole the trike from the family pick-up truck right outside their house Wednesday.
Gary and Loretta Martinez had not told their son Kyle because they thought he would be too confused and hurt by the theft.
They said they were not concerned with what happens to the thief, they just want the trike back.
Gary Martinez said he had left the $300 Triton in the pick-up truck overnight after coming home with Kyle.
The specially designed three-wheel cruiser helps the 14-year-old develop his coordination.
Loretta Martinez called the theft heartbreaking.
"It means everything to him," she said. "He rides it every day ... he just loves that bike. He even wore the wheels off that three times already."
The family said they cannot afford to replace the tricycle because the father is unemployed right now.
Anyone with information was asked to contact the Santa Ana Police Department at (714) 245-8400.