AIM-listed Time Out said it will hold a stake of 38% in the mobile payments app service following the investment.
Julio Bruno, chief executive of Time Out Group plc, said: "The ecosystem being built by Flypay is expanding fast and the investment by such a pioneering company as Just Eat proves just how valuable this business and its growth opportunity is."
Flypay enables integration between technology services for restaurant, pub and bar operators.
Time Out, which has expanded from a listings magazine into a global digital media and e-commerce group in recent years, has also begun to open food markets. It has one in Lisbon and has plans for London and New York.
Bruno added: "For Time Out this is a strategic investment in the future of our mobile B2B solutions for enterprise and hospitality clients.
"We believe it will enable us to integrate more closely with partners in the leisure and hospitality space and this will allow us to monetise businesses - one of our key strategic objectives."