Fonterra has spent $11.5 million to take a 10 per cent shareholding in Lithuania's biggest dairy producer, AB Rokiskio Suris.
The co-operative said the move would secure a supply line of high-value whey ingredients while opening up product options across Europe and the Middle East, and give it more opportunities to produce higher value products from New Zealand milk.
The investment is in line with Fonterra's strategy to grow its global sources of milk in strategic locations.
Chairman John Wilson said in a statement the investment would enable the co-op to further optimise the use of New Zealand milk and milk products.
"Our New Zealand farmers will always remain our primary source of milk, but increasingly we are supporting our growth and their returns through strategic partnerships in Europe, Latin America, Australia and China.