Sarah Hyland's Ex Matt Prokop Arrested For Allegedly Assaulting Girlfriend

Matt Prokop -- a former child actor who was the subject of a restraining order for allegedly abusing Sarah Hyland -- has been arrested in Texas, TMZ has learned.

Victoria PD Sergeant Dailey tells TMZ ... Prokop and his girlfriend were out together Saturday when she allegedly told someone Matt assaulted her. Police were called to the location, but say the two were gone when they arrived.

About an hour later, cops say they received a call about a disturbance at another spot in Victoria ... where they say they found Matt and his girlfriend.

In the course of their investigation ... Dailey says they were told Matt allegedly assaulted her by pushing her and slamming her head into something. They say she'd suffered enough injuries to warrant an arrest.

While they were taking Prokop into custody, police claim Matt tried to pull away from them and run. They're charging him with aggravated assault family and resisting arrest.

Prokop rose to fame in the mid-2000s with appearances on "The Office" and "Hannah Montana" before landing his major part as Zara in 'High School Musical 3.'

He dated "Modern Family" star Hyland for years before she obtained a restraining order against him, claiming he was verbally and physically abusive. He was ordered to stay away from Hyland for three years.

We've reached out to Propkop ... so far, no word back.