The Black Cats secured a narrow victory over the Owls at the Stadium of Light thanks to Ross Stewart's goal.
Darren Moore's Wednesday are looking to make an instant return to the Championship after they were relegated last year.
Meanwhile, Alex Neil hopes to stop Sunderland from playing a fifth consecutive campaign in England's third tier.
The fans on Wearside turned up in their numbers on Friday as 45,000 saw Sunderland win the first leg.
But there is still a long way to go in this tie, and the Owls thrashed Sunderland 3-0 at Hillsborough earlier in the season.
This should be an enticing and enthralling game, and the winner will face Wycome Wanderers at Wembley for a place in the Championship.
Sheffield Wednesday v Sunderland: talkSPORT coverage
This League One play-off semi-final will take place at Hillsborough tonight and will kick off at 7:45pm.
Commentary will come from Jim Proudfoot and former Sunderland and Wednesday man Micky Gray.
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Sheffield Wednesday v Sunderland: Team news
The home side could still be without Ciaran Brennan and Dominic Iorfa, as both recover from injuries.
Harlee Dean started the first leg after missing the last two games of the campaign, and is expected to be involved once more.
Moore could name an unchanged side from the one that lost on Friday, with Lee Gregory and Saido Berahino starting together.
Meanwhile, the visitors could be without Carl Winchester and Nathan Broadhead.
Broadhead, who's on loan from Everton, missed the first leg and remains a doubt for tonight's match as well.
Sheffield Wednesday v Sunderland: What has been said?
Sheffield Wednesday manager Darren Moore: "It's at a halfway mark now and we've just got to get ready for it. We're not counting our eggs and saying it's a foregone conclusion because it's not.
"We've got a lot of work to do, but we know we're going to have to play a lot better, certainly on the ball."
Sunderland head coach Alex Neil: "I want an open game, but I want us to be in control of it.
"I'm quite comfortable in admitting that I am a bit of control freak in terms of matches. If I don't feel that I'm in control, I need to change something.
"Obviously, there's only so much control you can have from the side of the pitch but providing I understand where their threat comes from, where we're vulnerable and how to protect it, and the lads understand all of that, I'm happy.
"The biggest fear for me was probably the last 10 minutes on Friday, when everyone was tired, nobody can hear you, the fans are all up, I'm trying to get information out on the pitch and people are going where they shouldn't be going - that's the point where you're just hoping that your players do the right things."