A bicycle bomb in 1939 left five people dead and about 70 injured but was overshadowed by the destruction inflicted on the city in World War Two.
An article by the BBC prompted a campaign by the victims' families to campaign for a memorial.
The tribute will be unveiled on 14 October, the council said.
The plaque will list the victims' names on a stone on Unity Lawn at Coventry Cathedral.
Coventry City Council, which is organising the event and funding the memorial, said it was important the victims were "never forgotten".
A date has been confirmed for a memorial in Coventry dedicated to five victims of a "forgotten" IRA attack on the city.