Five windows, including door panels, were smashed at Strawletterdallon Orange hall, near Newtownstewart in an attack discovered on Wednesday night.
Police described it as a sectarian hate crime.
The Orange Order said more windows were smashed at about 19:00 GMT on Thursday. The same hall was damaged five years ago in an arson attack.
The damage to the hall discovered on Wednesday is thought to have been caused during the previous night.
Inspector David McIlwaine said that the damage was caused to the rear of the building.
An Orange Order spokesman described those responsible as "mindless thugs intent on causing community division."
He said: "This was an act of wanton vandalism with the clear intention to cause damage and destruction to Orange property.
"However, the culprits are actually harming the wider community and groups who use the hall as a social hub and meeting place."
The Orange Order said that last year nine halls were targeted.
An Orange hall in County Tyrone has been attacked for the second time in two days.