St James Primary School in Southam and Newburgh Primary School in Warwick invited the grandparents to have lunch with their grandchildren.
Both schools have hailed the success of the events and are planning similar lunches in future.
Newburgh is hoping to open the next event to even more adults.
A Newburgh grandparent said: “Our granddaughter was so excited about it for days.
“It was lovely.”
Parents will be invited to St James later this term.
Hilary Wankling, the school’s headteacher, said: “Many grandparents commented that school dinners were never as good when they were young.”