The school will welcome visitors from 10am on Saturday, with access to explore the grounds, view classroom slideshows and examine displays featuring post-1995 centenary materials.
NSW Member for Murray Helen Dalton will be among the distinguished guests in attendance.
From 11am, the Finley Public School choir and local performer Jade Camden will entertain attendees, including a performance of the traditional school song.
At 2pm, formal proceedings will begin, featuring cake cutting and addresses from principal Owen Gill and assistant principal Cherilyn Taig.
Food and beverages will be available from Odesi Coffee Van and Rub N Smoke, owned by a former FPS student.
The day's events will conclude at 4pm.
The Sunday program kicks off at 8.30am with the P&C serving egg and bacon rolls for breakfast.
The celebration will end at 11am after final tours of the school.
Assistant principal Amanda Lyons expects the occasion to evoke nostalgic memories.
“It's a chance for past students, families and staff to come together and see how much has changed,” she said.
“Perhaps people can also reminisce with their old schoolmates.
“We were going to celebrate 125 years in 2020, but were unable to due to COVID-19.
“The Finley Rotaract reunion is also on during the long weekend.
“I don't think it was by decision to coincide, but it may work nicely for people to attend both events.”
While entry to the Coree St school celebrations is free, organisers ask attendees to register through the Finley Public School Facebook page event listing to help with catering planning.