The town will host the West Tyrone Last Saturday demonstration this year, with the main parade route closed to traffic from 11.30am.
Aughnacloy will also host a parade, affecting Dublin bound traffic.
Most parts of Omagh town centre fall within the parade route, along with the Campsie, Dublin Road and Crevenagh Road.
The PSNI have warned that there will be no parking along Campsie Road from Omagh County PS to the Swinging Bars roundabout and in High Street from the junction of Bridge Street to John Street.
“There will be no parking along Church Street from the Methodist Church to Georges Street and down to High Street.
“No waiting cones and double yellow line restrictions must be complied with. Disabled parking will be at suitable locations along the route and in Dunnes car park.
“Omagh – Derry traffic will not be affected but drivers should leave extra time to complete their journey safely and on time.
“Ballygawley – Cookstown or Gortin traffic will be diverted at Omagh Meats along the Bankmore Road, New Hospital Link Road, Donaghanie Road and Hospital Road.
“Police wish to advise street traders that they must have a valid Street Traders Licence and should make contact with the organisers of the event. We would like to apologise for the late notice. “Arrangements have, however, only now been finalised.”
Police have said motorists should expect delays and diversions around both Omagh and Aughnacloy.