The biggest donut chain restaurants in the world, based on the number of locations and global presence, include:

1. Dunkin’ (formerly Dunkin’ Donuts): With thousands of locations worldwide, Dunkin’ is one of the largest coffee and baked goods chains, famous for its donuts.
2. Krispy Kreme: Known for its iconic glazed donuts, Krispy Kreme has a significant international presence and a loyal following.
3. Tim Hortons: While primarily known for its coffee, Tim Hortons is a major player in the donut market, especially in Canada and other countries where it has expanded.
4. J.CO Donuts & Coffee: An Indonesian chain that has expanded to multiple countries, J.CO is known for its unique flavors and coffee offerings.
5. Mister Donut: Popular in Japan and other parts of Asia, Mister Donut offers a variety of donut flavors and other pastries.

These chains have expanded significantly beyond their countries of origin, establishing a strong international footprint.