The Tigers only just won the Anglo-Welsh Cup final yesterday, beating the Exeter Chiefs 16-12 at the Twickenham Stoop in London, while they remain very much in title contention in the Aviva Premiership, currently sitting in fifth place on 47 points, one point behind fourth-placed Bath with five games remaining in the regular season.
Perhaps Mauger's only downfall this season was Leicester's failure to qualify from their pool in the European Champions Cup, finishing third in Pool A behind Munster and Glasgow.
The former 46-test five-eighth will take charge of his final game for Leicester in their match against the Northampton Saints at Franklin's Gardens this weekend.
"We thank Aaron for his commitment to the club over the last two seasons as head coach and especially in his time in interim charge of team affairs in recent months," club chairman Tom said.
"We wish him well for the future."
O'Connor will leave his current position as Tonga's assistant coach to begin his second tenure at Welford Road early next month, subject to visa.