They acknowledged "no-one wants governments to tell people what they can eat" but cutting down red meat would be better for human health and for the earth.
Lead researcher Dr Marco Springmann said: "The consumption of red and processed meat exceeds recommended levels in most high and middle-income countries.
"This is having significant impacts not only on personal health, but also on healthcare systems, which are taxpayer-funded in many countries, and on the economy, which is losing its labour force due to ill health and care for family members who fall ill.
"I hope governments will consider introducing a health levy on red and processed meat to make healthy and sustainable decision-making easier for consumers.
"A health levy on red and processed meat would not limit choices, but send a powerful signal to consumers and take pressure off our healthcare systems."
The size of the meat tax would vary in different countries around the world, depending on how much meat they eat and how much it costs to buy.
The study estimated a tax could reduce the intake of processed meat like bacon and sausages by around two portions a week in high-income countries.