Northern Ireland, Wales and England are already through - but can the Republic join them?
Martin O'Neill's men take on Italy knowing they have to win to reach the last 16 of Euro 2016 - and, barring a huge win to cancel out their 3-0 loss to Belgium combined with a win for Sweden over the Belgians, the best they can do is to finish third.
Assuming they do finish third, they'll face either France or Croatia. Which one depends on whether or not the third-placed team in Group F also makes it through.
If they do, which looks likely (all that needs to happen is for Portugal to take at least a point off Hungary), Ireland will take on France. If not, Ireland will face Croatia.
Of course, for any of this to be relevant, Ireland have to beat Italy first. Over to you, lads...