The galaxy is about 30 billion light-years away and is helping scientists shed light on the period that immediately followed the Big Bang.
It was found using the Hubble Space Telescope and its distance was then confirmed with the ground-based Keck Observatory in Hawaii.
The study is published in the journal Nature.
Because it takes light so long to travel from the outer edge of the Universe to us, the galaxy appears as it was 13.1 billion years ago.
Lead researcher Steven Finkelstein, from the University of Texas at Austin, US, said: “This is the most distant galaxy we’ve confirmed. We are seeing this galaxy as it was 700 million years after the Big Bang.”
The far-off galaxy goes by the catchy name of z8_GND_5296.
Astronomers were able to measure how far it was from Earth by analysing its colour.
Because the Universe is expanding and everything is moving away from us, light waves are stretched. This makes objects look redder than they actually are.
Astronomers rate this apparent colour-change on a scale that is called redshift.
They found that this galaxy has a redshift of 7.51, beating the previous record-holder, which had a redshift of 7.21.
This makes it the most distant galaxy ever found.