The biggest crowd of the season at Portman Road watched Blues finish the campaign on a winning note thanks to goals from Tommy Smith and Paul Green.
Smith was on hand to put Blues in front just past the half hour mark after Daryl Murphy had been denied but Wednesday got a deserved equaliser early in the second-half through Kieran Lee.
Dean Gerken produced three excellent saves to keep the Owls at bay and it was Blues who won it, Paul Green getting on the end of a free-kick to head home midway through the second-half.
Town made two changes to the side that went down at Burnley, Anthony Wordsworth and Frank Nouble coming in for Stephen Hunt and the injured Cole Skuse.
Wednesday, backed by a travelling support of 2000, started on the front foot and Michail Antonio’s pace got him behind the Town defence but his cross failed to trouble Dean Gerken.
Antonio’s shot was blocked by Luke Chambers, the Town skipper then doing really well to get a challenge in on Antonio again after the winger found space in the Blues’ box.
Former Town Academy player Caolan Lavery, making his first appearance at Portman Road as a professional, saw a cross deflected behind by Aaron Cresswell as Wednesday continued to threaten on the break, while at the other end a terrific tackle by Glenn Loovens robbed Jonny Williams as the Palace loanee burst into the box in Town’s first real threat at goal.
Atdhe Nuhiu headed wide, Wordsworth’s free-kick skimmed across goal then Sam Hutchinson robbed Nouble with a superb challenge as the Town frontman threatened to make the breakthrough.
Williams’ cross was cleared by Loovens as Murphy looked to convert, but on 36 minutes Town went ahead, Murphy denied by the hand of Damian Martinez after Green’s excellent pass but Smith was on hand to volley in the rebound from four yards out.
Murphy was inches away from making it two when he cut inside and curled the ball past Martinez but it came back off the inside of the post and was cleared.
Lavery almost found the equaliser just before the break, his left foot shot deflected wide superbly by Gerken, the ‘keeper then showing great reflexes to keep out Antonio from close range to keep Blues ahead at half-time.
Murphy headed over from Cresswell’s wicked delivery, Wednesday’s Nuhiu following suit at the other end from Chris Maguire’s cross.
The Owls got the goal they had threatened from kick-off on 55 minutes, Joe Mattock’s cross was missed by Lavery but the ball rebounded back to Lee who passed it into the net.
Maguire tested Gerken from distance with a powerful strike, with the Owls making a first change with Nuhiu replaced by Leon Best. Town followed with Smith replaced by Paul Taylor and Williams by Hunt.
Republic of Ireland international Hunt made an instant impact, his free-kick glanced in by Green on 67 minutes for his second successive goal at Portman Road.
Jeremy Helan replaced Mattock for the last 15 minutes, Jacques Maghoma also joining the action, Giles Coke making way with the substitute firing just wide with his first touch.
Hutchinson’s volley looked destined to find the net until Cresswell’s head intervened, Jack Marriott coming on for his home debut with five minutes left on the clock.
Wednesday kept pressing for an equaliser but Blues held firm to finish the season with three points and a ninth place berth.