Mr Rees-Mogg told the Commons he had drawn Scotland in a sweepstake organised amongst senior parliamentary figures.
The Leader of the House of Commons was asked by the SNP’s Owen Thompson MP to offer best wishes to both teams.
Speaking during business questions on Thursday, Mr Rees-Mogg said: “The corridor of the Chairman of Ways and Means has a sweepstake and in the sweepstake I have been fortunate enough to draw Scotland.
“So I shall have very divided loyalties tomorrow, but I’m glad to say that it is very encouraging for the Union.
“I was pleased to see Wales do well yesterday and the Rees side of me was coming to the fore, and I am looking forward to supporting whichever side does best because I have an interest in all three of them doing well.”
Mr Thompson had asked of Mr Rees-Mogg: “Tomorrow both of our nations are independently represented at the Euros tomorrow evening, and while I have a dream I’m sure many would agree that neither the Leader or I would perhaps be the best example of who can boogie, but can he join with me in wishing both teams all the very best for a Scotland victory?”
Mr Rees-Mogg was elected as MP for North East Somerset in 2010 and is now in charge of government business in the Commons, but also boasts Welsh heritage.
The old Etonian also contested the seat of Central Fife at the 1997 general election, campaigning with the family’s nanny, Veronica Crook, in tow.
Labour’s Kevin Brennan (Cardiff West) joked: “The Leader of the House is very proud of his Welsh roots and congratulated the Welsh team earlier on.
“Could he pass on my commiserations to the Prime Minister who I know is equally proud of his Turkish roots at the 2-0 defeat of Turkey last night?
“A good reminder to him that Wales are in the tournament, which of course he didn’t realise last week.”
Scotland play England at Wembley Stadium from 8pm.