The rare babies - a boy and a girl - were born three months ago and for the first time ever both twins have survived.
Their 13-year-old mum, Nyabitondore, gave birth to the babies in the Volcanoes National Park in Rwanda.
Experts are keeping a close eye on the new family just in case the mum needs a hand raising her new babies.
Although both twins are healthy, they will need their mother to look after them until they are about three years old.
Endangered species
The new additions are part of the Susa group, which has 37 members and is the biggest mountain gorilla troop left in the world.
Mountain gorillas are an endangered species but things are looking up for the rare primates as at least 14 babies have been born in the last year.
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