Local Shop Week, which starts on April 21, will see parents of children at St Joseph's Primary pledging to buy goods and services from the shops, which in return will support their campaign.
Parents are fighting to save closure- threatened St Joseph's from operating in a shared campus with St Andrew's in Bearsden.
They say the move, if it goes ahead, will mean an end to Catholic education in Milngavie.
Campaign spokesman Gary Lawson said: "The local traders obviously realise the importance of keeping the children and the families of St Joseph's within the local community.
"They have supported us throughout our campaign.
"It's crucial for them that the children and their families are not displaced to another community.
"This is vital for our local economy.
"The traders' busiest times during the week are during lunchtime and after 3pm, when the schools come out.
"Yesterday was all about launching an initiative whereby all the parents will shop locally during that week to get their necessities.
"The focus will be on local independent traders, especially."
Some 30 traders will be involved, including a butcher's, fishmonger's, ladies' fashion shop, charity shops and local branches of RS McColl and Costa Coffee.